UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   FORM N-CSR

                   CERTIFIED SHAREHOLDER REPORT OF REGISTERED
                        MANAGEMENT INVESTMENT COMPANIES



		Investment Company Act file number 811-21321

                          Pioneer Municipal High Income Trust
               (Exact name of registrant as specified in charter)


                       60 State Street, Boston, MA 02109
              (Address of principal executive offices) (ZIP code)


            Terrence J. Cullen, Amundi Pioneer Asset Management, Inc.,
                       60 State Street, Boston, MA 02109
                    (Name and address of agent for service)


Registrant's telephone number, including area code:  (617) 742-7825


Date of fiscal year end:  April 30


Date of reporting period:  May 1, 2018 through October 31, 2018


Form N-CSR is to be used by management investment companies to file reports with
the Commission not later than 10 days after the transmission to stockholders of
any report that is required to be transmitted to stockholders under Rule 30e-1
under the Investment Company Act of 1940 (17 CFR 270.30e-1).  The Commission may
use the information provided on Form N-CSR in its regulatory, disclosure review,
inspection, and policymaking roles.

A registrant is required to disclose the information specified by Form N-CSR,
and the Commission will make this information public. A registrant is not
required to respond to the collection of information contained in Form N-CSR
unless the Form displays a currently valid Office of Management and Budget
("OMB") control number. Please direct comments concerning the accuracy of the
information collection burden estimate and any suggestions for reducing the
burden to Secretary, Securities and Exchange Commission, 450 Fifth Street, NW,
Washington, DC 20549-0609.  The OMB has reviewed this collection of information
under the clearance requirements of 44 U.S.C. ss. 3507.


ITEM 1. REPORTS TO STOCKHOLDERS.


                             Pioneer Municipal High
                             Income Trust

--------------------------------------------------------------------------------
                             Semiannual Report | October 31, 2018
--------------------------------------------------------------------------------

                             Ticker Symbol:    MHI

                             [LOGO]   Amundi Pioneer
                                      ==============
                                    ASSET MANAGEMENT



                             visit us: www.amundipioneer.com



Table of Contents



                                                                          
President's Letter                                                            2

Portfolio Management Discussion                                               4

Portfolio Summary                                                            10

Prices and Distributions                                                     11

Performance Update                                                           12

Schedule of Investments                                                      13

Financial Statements                                                         23

Financial Highlights                                                         26

Notes to Financial Statements                                                28

Additional Information                                                       38

Approval of Investment Management Agreement                                  41

Trustees, Officers and Service Providers                                     45


            Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 1



President's Letter

Despite economic news that has remained generally positive throughout 2018,
market volatility has increased significantly this year compared with 2017.
October was a particularly poor month for both U.S. and global equity markets,
as every major stock market index finished the month in negative territory.
Results have been more mixed on the fixed-income side, with rising interest
rates pushing down most year-to-date returns.

On the economic front, U.S. gross domestic product (GDP) growth exceeded 4% in
the second quarter of 2018 and topped 3% once again in the third quarter. The
low unemployment rate has continued, with initial jobless claims recently
hitting a multi-decade low and consumer and small-business confidence also
achieving levels not seen in many years.

Despite the good economic news, and even though wages have been rising,
inflation expectations have not risen significantly. For its part, the U.S.
Federal Reserve System (the Fed) has continued with its tightening of monetary
policy by raising interest rates three times in 2018, while moving forward with
the tapering of its balance sheet, a process which began in October 2017.

The greater market volatility this year as compared to last year has been
driven by several factors. The aforementioned rising interest rates have been
one reason, while the uncertainty surrounding U.S. trade policy has, at times,
also led to unsettled markets. Of course, in today's global economy, risk
factors extend well beyond U.S. borders, and in recent months investors have
grappled with various issues on the international front, including questions
surrounding the United Kingdom's Brexit negotiations, concerns about the
budgetary policies of the populist Italian government, and the potential impact
of Turkey's economic challenges on European banks. Moreover, while trade
tensions between the U.S. and Europe have moderated, questions about the future
of the U.S./China trade relationship remain unresolved, and any major fracture
in that relationship could have a negative impact on China's economy and, by
extension, on its Asian trade partners.

With regard to our market outlook, over the medium term, we believe the
fundamental investment case for U.S. equities remains in place, with support
from the fairly positive economic backdrop and with an additional lift
potentially coming from the investment side as U.S. businesses consider
increasing capital expenditures. We do believe market volatility will persist
and, therefore, careful selection of investment themes, sector allocations, and
individual stocks will be increasingly relevant to overall performance, as the

2 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



maturity of the economic and market cycles could eventually become headwinds.
We believe a focus on owning shares of quality companies trading at reasonable
prices is key to navigating the current equity-market phase.

In fixed income, we have taken a more cautious approach across our core
portfolios with regard to credit-sensitive debt such as corporate bonds,
favoring quality and liquidity. As interest rates have risen, we find that
short- and intermediate-term U.S. Treasuries have become more attractive, and
that agency mortgage-backed securities (MBS) and high-quality, non-agency MBS
now also offer lower downside risk. In general, we think structured sectors
(such as asset-backed securities and MBS) are more attractive than corporate
sectors.

We believe this year's market fluctuations as well as increased risk factors
within the global economy have served to remind investors of the importance of
active management. Since 1928, active management has been the foundation of
Amundi Pioneer's investment approach. We believe active management is
especially important during periods of volatility, and that our shareowners can
benefit from the experience and tenure of our investment teams, who work
collaboratively to make active and informed decisions across our funds.

As always, and particularly during times of market uncertainty, we encourage
you to work with your financial advisor to develop an overall investment plan
that addresses both your short- and long-term goals, and to implement such a
plan in a disciplined manner.

We greatly appreciate the trust you have placed in us and look forward to
continuing to serve you in the future.

Sincerely,

/s/ Lisa M. Jones

Lisa M. Jones
Head of the Americas, President and CEO of U.S.
Amundi Pioneer Asset Management USA, Inc.
October 31, 2018

Any information in this shareowner report regarding market or economic trends
or the factors influencing the Trust's historical or future performance are
statements of opinion as of the date of this report. Past performance is no
guarantee of future results.

            Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 3



Portfolio Management Discussion | 10/31/18

The municipal bond market generated marginally positive results over the
six-month period ended October 31, 2018, with high-yield municipals once again
outperforming investment-grade municipals. In the following interview, David
Eurkus and Jonathan Chirunga discuss the factors that influenced the
performance of Pioneer Municipal High Income Trust during the six-month period.
Mr. Eurkus, Managing Director, Director of Municipals, U.S., and a portfolio
manager at Amundi Pioneer Asset Management, Inc. ("Amundi Pioneer"), and Mr.
Chirunga, a senior vice president and a portfolio manager at Amundi Pioneer,
are responsible for the day-to-day management of the Trust.

Q     How did Pioneer Municipal High Income Trust perform during the six-month
      period ended October 31, 2018?

A     Pioneer Municipal High Income Trust returned 0.09% at net asset value
      (NAV) and -1.50% at market price during the six-month period ended October
      31, 2018. During the same six-month period, the Trust's benchmarks, the
      Bloomberg Barclays U.S. Municipal High Yield Bond Index and the Bloomberg
      Barclays Municipal Bond Index, returned 2.08% and 0.46% at NAV,
      respectively. The Bloomberg Barclays U.S. Municipal High Yield Bond Index
      is an unmanaged measure of the performance of lower-rated municipal bonds,
      while the Bloomberg Barclays Municipal Bond Index is an unmanaged measure
      of the performance of investment-grade municipal bonds. Unlike the Trust,
      the two indices do not use leverage. While use of leverage increases
      investment opportunity, it also increases investment risk.

      During the same six-month period, the average return at NAV of the 15
      closed-end funds in Morningstar's High Yield Municipal Debt Closed End
      Funds category (which may or may not be leveraged) was 0.49%, and the
      average return at market price of the 15 closed-end funds in the same
      Morningstar category was -1.60%.

      The shares of the Trust were selling at an 11.4% discount to NAV on
      October 31, 2018. Comparatively, the shares of the Trust were selling at a
      10.0% discount to NAV on April 30, 2018.

      On October 31, 2018, the standardized 30-day SEC yield of the Trust's
      shares was 4.06%*.

*     The 30-day SEC yield is a standardized formula that is based on the
      hypothetical annualized earning power (investment income only) of the
      Trust's portfolio securities during the period indicated.

4 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



Q     How would you describe the investment environment in the municipal bond
      market during the six-month period ended October 31, 2018?

A     During the past six months, the municipal bond market performed well in
      the wake of tax reform legislation passed in the U.S. last December, which
      continued to loom large. The law's changes to the federal tax code
      included the provision that, within the municipal market, interest income
      on advance refunding bonds issued after December 31, 2017, would be
      treated as taxable income for the investor. (An advance refunding bond is
      issued to retire, or pre-refund, another outstanding bond more than 90
      days in advance of its call date.)

      Advance refunding bonds have traditionally been issued by municipalities
      to refinance debt at lower rates. In December 2017, a host of municipal
      entities rushed to issue advance refunding bonds before the new tax bill
      took effect. The spike in supply was well received by the market, but in
      January 2018, the municipal market experienced significantly reduced
      demand, as many large investors who would have typically purchased bonds
      in January had already done so in December. Due to the sudden decrease in
      demand, the tax-free bond market underwent a correction, and yields rose
      sharply. However, the municipal market then stabilized.

      Later in the period, the high-yield municipal market was temporarily
      disrupted when some large exchange-traded funds (ETFs) began to liquidate
      a significant volume of tobacco settlement bonds in order to cover
      redemptions. However, the heavily discounted bonds began to find buyers by
      period-end, and tobacco settlement bonds specifically -- and high-yield
      municipals more generally -- gradually recovered in price. Municipal bonds
      ended the six-month period at valuations that were very attractive
      compared with Treasury bonds of similar maturity. Meanwhile, investor
      demand for tax-exempt bonds continued to outpace supply.

      Elsewhere, the U.S. economy continued to perform well despite increasing
      trade tensions between the United States and a number of other countries,
      and the U.S. Federal Reserve System (the Fed) continued to remove monetary
      accommodation from the U.S. economy by raising short-term rates in June
      and September, and continuing to taper its balance sheet, a process that
      began in October 2017. In addition, the Treasury yield curve continued to
      flatten over the period, as long-term Treasury rates rose slightly while
      short-term rates increased more significantly.

            Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 5



Q     What factors affected the Trust's performance relative to the Bloomberg
      Barclays indices during the six-month period ended October 31, 2018?

A     During the period, the Trust's portfolio remained well-diversified**, with
      exposures to both investment-grade and high-yield municipal bonds.

      The Trust's return lagged the returns of both Bloomberg Barclays municipal
      indices during the period, as key detractors from benchmark-relative
      performance included the portfolio's holdings of bonds issued by Sanger
      (Texas) Industrial Development Corporation, which experienced ongoing
      credit problems that contributed to a moderate decrease in value, and
      revenue bonds issued by the State of Illinois.

      On the positive side, the portfolio's holdings of certain tobacco bonds
      funded by Master Settlement Agreements between the tobacco industry and
      individual states, as well as public finance authority bonds issued by the
      State of Wisconsin, contributed to the Trust's benchmark-relative returns
      during the period.

Q     Did the Trust's distributions*** to shareholders change during the
      six-month period ended October 31, 2018?

A     No, the Trust's distributions were unchanged over the six-month period.

Q     Did the level of leverage in the Trust change during the six-month period
      ended October 31, 2018?

A     At the end of the six-month period on October 31, 2018, 31.1% of the
      Trust's total managed assets were financed by leverage obtained through
      the issuance of preferred shares, compared with 30.5% of the Trust's total
      managed assets financed by leverage at the start of the period on April 1,
      2018.

      The Trust historically employed leverage through the issuance of Auction
      Preferred Shares ("APS"). The Trust redeemed all of its outstanding APS on
      February 14, 2018, and February 15, 2018. The Trust refinanced the APS,
      and increased the amount of leverage employed by the Trust, through the
      issuance of Variable Rate Muni Fund Term Preferred Shares ("VMTP Shares").
      VMTP Shares are issued via private placement and are not publicly
      available. The further increase in leverage as a percentage of the Trust's
      total managed assets during the six-month period was the result of
      depreciation in the values of the Trust's holdings.

**    Diversification does not assure a profit nor protect against loss.

***   Distributions are not guaranteed.

6 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



Q     Did the Trust invest in any derivative securities during the six-month
      period ended October 31, 2018?

A     No, the Trust did not hold derivative securities during the period.

Q     What is your investment outlook?

A     Our outlook for the municipal market remains positive. We believe that
      healthy demand from both traditional and non-traditional investors drawn
      to the market by the attractive value and generous yields of municipal
      bonds -- as compared with taxable debt -- can continue to outstrip limited
      new-issue supply and help to support the prices of municipals. At the same
      time, we think that the U.S. economy can continue to grow at a steady pace
      without an accompanying acceleration in inflation. Given such an economic
      scenario, we believe municipal bonds with strong credit characteristics
      should continue to experience credit improvement. We also believe that the
      Fed will continue to act deliberately and cautiously as it gradually
      raises short-term rates. However, escalating trade disputes and other
      geopolitical events could spur additional volatility within financial
      markets in the coming months.

      Consistent with our investment discipline in managing the Trust, we intend
      to focus on intensive, fundamental research when selecting individual bond
      issues, while maintaining a close watch on any economic factors that could
      influence the municipal market. We do not anticipate any significant
      changes to either the portfolio's positioning or structure in the near
      future.

            Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 7



Please refer to the Schedule of Investments on pages 13-22 for a full listing
of Trust securities.

All investments are subject to risk, including the possible loss of principal.
In the past several years, financial markets have experienced increased
volatility, depressed valuations, decreased liquidity and heightened
uncertainty. These conditions may continue, recur, worsen or spread.

Investments in high-yield or lower-rated securities are subject to
greater-than-average risk.

The Trust may invest in securities of issuers that are in default or that are
in bankruptcy.

A portion of income may be subject to state, federal, and/or alternative
minimum tax. Capital gains, if any, are subject to a capital gains tax.

When interest rates rise, the prices of debt securities held by the Trust will
generally fall. Conversely, when interest rates fall the prices of debt
securities held by the Trust generally will rise.

Interest rates in the U.S. recently have been historically low, but have begun
to rise, and so the Trust faces a heightened risk that interest rates may
continue to increase. A general rise in interest rates could adversely affect
the price and liquidity of fixed income securities.

By concentrating in municipal securities, the Trust is more susceptible to
adverse economic, political or regulatory developments than is a portfolio that
invests more broadly.

Investments in the Trust are subject to possible loss due to the financial
failure of the issuers of the underlying securities and the issuers' inability
to meet their debt obligations.

The Trust may invest up to 20% of its total assets in illiquid securities.
Illiquid securities may be difficult to dispose of at a price reflective of
their value at the times when the Trust believes it is desirable to do so, and
the market price of illiquid securities is generally more volatile than that of
more liquid securities. Illiquid securities are also more difficult to value
and investment of the Trust's assets in illiquid securities may restrict the
Trust's ability to take advantage of market opportunities.

The Trust uses leverage through the issuance of preferred shares. Leverage
creates significant risks, including the risk that the Trust's incremental
income or capital appreciation for investments purchased with the proceeds of
leverage will not be sufficient to cover the cost of the leverage, which may
adversely affect the return for the holders of common shares.

8 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



The Trust is required to maintain certain regulatory, rating agency and other
asset coverage requirements in connection with its outstanding preferred
shares. In order to maintain required asset coverage levels, the Trust may be
required to alter the composition of its investment portfolio or take other
actions, such as redeeming preferred shares with the proceeds from portfolio
transactions, at what might be inopportune times in the market. Such actions
could reduce the net earnings or returns to holders of the Trust's common
shares over time, which is likely to result in a decrease in the market value
of the Trust's shares.

These risks may increase share price volatility.

Any information in this shareholder report regarding market or economic trends
or the factors influencing the Fund's historical or future performance are
statements of opinion as of the date of this report. Past performance is no
guarantee of future results.

            Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 9



Portfolio Summary | 10/31/18

Portfolio Diversification
--------------------------------------------------------------------------------
(As a percentage of total investments)*

[THE FOLLOWING DATA WAS REPRESENTED AS A PIE CHART IN THE PRINTED MATERIAL]



                                                                        
Insured                                                                    13.8%
Other Revenue                                                              33.5%
Education Revenue                                                          12.9%
Health Revenue                                                             10.5%
Development Revenue                                                         9.0%
Facilities Revenue                                                          7.7%
Tobacco Revenue                                                             6.7%
Water Revenue                                                               2.2%
Airport Revenue                                                             1.8%
Pollution Control Revenue                                                   1.2%
Transportation Revenue                                                      0.7%


10 Largest Holdings
--------------------------------------------------------------------------------
(As a percentage of total investments)*



                                                                                                       
 1. Metropolitan Pier & Exposition Authority, McCormick Place, 5.65%, 6/15/22
    (NATL-RE Insured)                                                                                     3.76%
---------------------------------------------------------------------------------------------------------------
 2. State of Washington, Motor Vehicle Sales Tax, Series C, 6/1/22 (NATL Insured)                         3.30
---------------------------------------------------------------------------------------------------------------
 3. Massachusetts Development Finance Agency, WGBH Foundation, Series A,
    5.75%, 1/1/42 (AMBAC Insured)                                                                         2.27
---------------------------------------------------------------------------------------------------------------
 4. New York State Dormitory Authority, Series C, 5.0%, 3/15/39                                           2.06
---------------------------------------------------------------------------------------------------------------
 5. New York State Dormitory Authority, Series A, 4.0%, 7/1/41                                            2.04
---------------------------------------------------------------------------------------------------------------
 6. State of Minnesota, Series B, 4.0%, 8/1/27                                                            1.65
---------------------------------------------------------------------------------------------------------------
 7. District of Columbia Tobacco Settlement Financing Corp., Asset-Backed, 6.75%, 5/15/40                 1.57
---------------------------------------------------------------------------------------------------------------
 8. Buckeye Tobacco Settlement Financing Authority, Asset-Backed, Series A-2, 6.5%, 6/1/47                1.53
---------------------------------------------------------------------------------------------------------------
 9. Massachusetts Development Finance Agency, Harvard University, Series A, 5.0%, 7/15/40                 1.53
---------------------------------------------------------------------------------------------------------------
10. Michigan Tobacco Settlement Finance Authority, Series A, 6.0%, 6/1/48                                 1.51
---------------------------------------------------------------------------------------------------------------


*     Excludes temporary cash investments and all derivative contracts except
      for options purchased. The Trust is actively managed, and current holdings
      may be different. The holdings listed should not be considered
      recommendations to buy or sell any securities listed.

10 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



Prices and Distributions | 10/31/18

Market Value per Common Share^
--------------------------------------------------------------------------------



--------------------------------------------------------------------------------
                                  10/31/18                 4/30/18
--------------------------------------------------------------------------------
                                                     
Market Value                      $10.78                   $11.25
--------------------------------------------------------------------------------
Discount                          (11.4)%                  (10.0)%
--------------------------------------------------------------------------------


Net Asset Value per Common Share^
--------------------------------------------------------------------------------



--------------------------------------------------------------------------------
                                  10/31/18                 4/30/18
--------------------------------------------------------------------------------
                                                     
Net Asset Value                   $12.17                   $12.50
--------------------------------------------------------------------------------


Distributions per Common Share:
--------------------------------------------------------------------------------



--------------------------------------------------------------------------------
                           Net Investment     Short-Term       Long-Term
                              Income         Capital Gains    Capital Gains
--------------------------------------------------------------------------------
                                                        
5/1/18 -- 10/31/18            $0.3150           $ --             $ --
--------------------------------------------------------------------------------


Yields
--------------------------------------------------------------------------------



--------------------------------------------------------------------------------
                                  10/31/18                 4/30/18
--------------------------------------------------------------------------------
                                                     
30-Day SEC Yield                  4.06%                    3.43%
--------------------------------------------------------------------------------


The data shown above represents past performance, which is no guarantee of
future results.

^     Net asset value and market value are published in Barron's on Saturday,
      The Wall Street Journal on Monday and The New York Times on Monday and
      Saturday. Net asset value and market value are published daily on the
      Trust's website at www.amundipioneer.com.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 11



Performance Update | 10/31/18

Investment Returns
--------------------------------------------------------------------------------
The mountain chart on the right shows the change in market value, including
reinvestment of dividends and distributions, of a $10,000 investment made in
common shares of Pioneer Municipal High Income Trust during the periods shown,
compared to that of the Bloomberg Barclays Municipal Bond Index and Bloomberg
Barclays U.S. Municipal High Yield Bond Index.



Average Annual Total Returns
(As of October 31, 2018)
-----------------------------------------------------------------
                                                    BBG
                                      BBG           Barclays
                                      Barclays      U.S.
                 Net                  Municipal     Municipal
                 Asset                Bond          High Yield
                 Value     Market     Index         Bond Index
Period           (NAV)     Price      (NAV)         (NAV)
-----------------------------------------------------------------
                                        
10 years         8.73%      8.81%      4.80%        7.45%
5 years          5.03       0.66       3.25         5.96
1 year           0.60      -2.99      -0.51         4.74
-----------------------------------------------------------------


[THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL]

Value of $10,000 Investment



           Pioneer Municipal    Bloomberg Barclays     Bloomberg Barclays U.S. Municipal
           High Income Trust    Municipal Bond Index   High Yield Bond Index
                                              
10/08      $10,000              $10,000                $10,000
10/09      $15,110              $11,360                $11,454
10/10      $18,657              $12,243                $13,041
10/11      $19,224              $12,707                $13,480
10/12      $23,304              $13,854                $15,762
10/13      $22,511              $13,615                $15,365
10/14      $26,019              $14,680                $17,031
10/15      $24,031              $15,101                $17,516
10/16      $24,522              $15,714                $19,025
10/17      $23,979              $16,058                $19,594
10/18      $23,261              $15,976                $20,523


Call 1-800-225-6292 or visit www.amundipioneer.com for the most recent
month-end performance results. Current performance may be lower or higher than
the performance data quoted.

Performance data shown represents past performance. Past performance is no
guarantee of future results. Investment return and market price will fluctuate,
and your shares may trade below NAV due to such factors as interest rate
changes and the perceived credit quality of borrowers.

Total investment return does not reflect broker sales charges or commissions.
All performance is for common shares of the Trust.

Shares of closed-end funds, unlike open-end funds, are not continuously
offered. There is a one-time public offering and, once issued, shares of
closed-end funds are bought and sold in the open market through a stock
exchange and frequently trade at prices lower than their NAV. NAV per common
share is total assets less total liabilities, which include preferred shares or
borrowings, as applicable, divided by the number of common shares outstanding.

When NAV is lower than market price, dividends are assumed to be reinvested at
the greater of NAV or 95% of the market price. When NAV is higher, dividends
are assumed to be reinvested at prices obtained through open-market purchases
under the Trust's dividend reinvestment plan.

The performance table and graph do not reflect the deduction of fees and taxes
that a shareowner would pay on Trust distributions or the sale of Trust shares.
Had these fees and taxes been reflected, performance would have been lower.

The Bloomberg Barclays Municipal Bond Index is an unmanaged, broad measure of
the municipal bond market. The Bloomberg Barclays High Yield Municipal Bond
Index is unmanaged, totals over $26 billion in market value and maintains over
1,300 securities. Municipal bonds in this index have the following
requirements: maturities of one year or greater, sub investment grade (below
Baa or non-rated), fixed coupon rate, issued after 12/31/90, deal size over $20
million, and maturity size of at least $3 million. Index returns are calculated
monthly, assume reinvestment of dividends and, unlike Trust returns, do not
reflect any fees, expenses or sales charges. The indices do not use leverage.
It is not possible to invest directly in the indices.

12 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



Schedule of Investments | 10/31/18 (unaudited)



----------------------------------------------------------------------------------------------------------------------
Principal
Amount
USD ($)                                                                                                  Value
----------------------------------------------------------------------------------------------------------------------
                                                                                                   
                        UNAFFILIATED ISSUERS -- 143.1%
                        DEBTOR IN POSSESSION FINANCING --
                        0.9% of Net Assets
  2,522,000             Texas Pellets, Inc. / German Pellets Texas LLC, 8.0%,
                        9/30/18 (144A)                                                                   $   2,522,000
                                                                                                         -------------
                        Total Diversified Financials                                                     $   2,522,000
----------------------------------------------------------------------------------------------------------------------
                        TOTAL DEBTOR IN POSSESSION FINANCING
                        (Cost $2,522,000)                                                                $   2,522,000
----------------------------------------------------------------------------------------------------------------------
                        TAX EXEMPT OBLIGATIONS --
                        142.2% of Net Assets(a)
                        Arizona -- 2.9%
  1,000,000             Arizona Industrial Development Authority, Bridgewater
                        Avondale Project, 5.375%, 1/1/38                                                 $     970,250
  4,000,000(b)          City of Phoenix, 5.0%, 7/1/27                                                        4,629,920
  2,250,000             City of Phoenix, Industrial Development Authority, 3rd &
                        Indian School Assisted Living Project, 5.4%, 10/1/36                                 2,280,240
     24,000             County of Pima, Industrial Development Authority, Arizona
                        Charter Schools Project, Series C, 6.75%, 7/1/31                                        24,033
                                                                                                         -------------
                                                                                                         $   7,904,443
----------------------------------------------------------------------------------------------------------------------
                        California -- 6.9%
 10,000,000(c)          California County Tobacco Securitization Agency, Capital
                        Appreciation, Stanislaus County, Subordinated,
                        Series A, 6/1/46                                                                 $   1,632,800
  1,450,000             California Enterprise Development Authority, Sunpower
                        Corp., 8.5%, 4/1/31                                                                  1,526,227
    530,000             California Municipal Finance Authority, Santa Rosa
                        Academy Project, Series A, 5.75%, 7/1/30                                               562,213
  4,750,000             California Pollution Control Financing Authority, 5.0%,
                        7/1/37 (144A)                                                                        4,782,062
  1,725,000(d)          California School Finance Authority, Classical Academies
                        Project, Series A, 7.375%, 10/1/43                                                   1,988,459
  1,400,000             California Statewide Communities Development Authority,
                        Lancer Plaza Project, 5.625%, 11/1/33                                                1,537,326
    568,006(e)          California Statewide Communities Development Authority,
                        Microgy Holdings Project, 9.0%, 12/1/38                                                      6
  2,000,000(b)          Los Angeles Community College District, Series G,
                        4.0%, 8/1/39                                                                         2,036,940
  1,605,000             Los Angeles County Metropolitan Transportation Authority,
                        Series A, 5.0%, 7/1/30                                                               1,873,565
  3,000,000             Tobacco Securitization Authority of Southern California,
                        Series A-1, 5.0%, 6/1/37                                                             3,007,440
                                                                                                         -------------
                                                                                                         $  18,947,038
----------------------------------------------------------------------------------------------------------------------


The accompanying notes are an integral part of these financial statements.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 13



Schedule of Investments | 10/31/18 (unaudited) (continued)



----------------------------------------------------------------------------------------------------------------------
Principal
Amount
USD ($)                                                                                                  Value
----------------------------------------------------------------------------------------------------------------------
                                                                                                   
                        Colorado -- 1.4%
  1,500,000(d)          Colorado Educational & Cultural Facilities Authority, Rocky
                        Mountain Classical Academy Project, 8.0%, 9/1/43                                 $   1,877,010
  1,665,000+(c)(f)      Tender Option Bond Trust Receipts/Certificates, RIB,
                        Series 2018, 6/1/39 (144A)                                                           1,966,631
                                                                                                         -------------
                                                                                                         $   3,843,641
----------------------------------------------------------------------------------------------------------------------
                        Connecticut -- 3.3%
  2,915,000             Mohegan Tribal Finance Authority, 7.0%, 2/1/45 (144A)                            $   2,951,787
  5,000,000(b)          State of Connecticut, Series E, 4.0%, 9/1/30                                         5,083,050
  1,000,000             Town of Hamden, Whitney Center Project, Series A,
                        7.75%, 1/1/43                                                                        1,029,700
                                                                                                         -------------
                                                                                                         $   9,064,537
----------------------------------------------------------------------------------------------------------------------
                        District of Columbia -- 6.5%
  3,705,000             District of Columbia Tobacco Settlement Financing Corp.,
                        Asset-Backed, 6.5%, 5/15/33                                                      $   4,037,413
  6,000,000             District of Columbia Tobacco Settlement Financing Corp.,
                        Asset-Backed, 6.75%, 5/15/40                                                         6,208,500
 25,000,000(c)          District of Columbia Tobacco Settlement Financing Corp.,
                        Capital Appreciation, Asset-Backed, Series A, 6/15/46                                3,818,750
  3,975,000             District of Columbia, Deed Tax Housing Product Trust Fund,
                        Series A, 4.25%, 6/1/37 (NATL Insured)                                               3,980,326
                                                                                                         -------------
                                                                                                         $  18,044,989
----------------------------------------------------------------------------------------------------------------------
                        Florida -- 6.1%
  1,500,000             Alachua County Health Facilities Authority, Terraces Bonita
                        Springs Project, Series A, 8.125%, 11/15/41                                      $   1,643,745
  1,500,000             Alachua County Health Facilities Authority, Terraces Bonita
                        Springs Project, Series A, 8.125%, 11/15/46                                          1,639,320
  2,500,000(d)          County of Miami-Dade, Aviation Revenue, Series B,
                        5.5%, 10/1/41                                                                        2,579,725
  5,000,000             County of Miami-Dade, Water & Sewer System Revenue,
                        Series A, 4.0%, 10/1/44                                                              4,952,050
  5,000,000             Florida's Turnpike Enterprise, Department of Transportation,
                        Series A, 4.0%, 7/1/34                                                               5,109,200
  1,000,000(d)          Hillsborough County Industrial Development Authority,
                        Various Health Facilities, 8.0%, 8/15/32                                             1,055,870
                                                                                                         -------------
                                                                                                         $  16,979,910
----------------------------------------------------------------------------------------------------------------------
                        Georgia -- 2.6%
  2,500,000             Clayton County Development Authority, Delta Air Lines,
                        Series A, 8.75%, 6/1/29                                                          $   2,721,800
  4,000,000             Private Colleges & Universities Authority, Emory
                        University, Series A, 5.0%, 10/1/43                                                  4,357,160
                                                                                                         -------------
                                                                                                         $   7,078,960
----------------------------------------------------------------------------------------------------------------------


The accompanying notes are an integral part of these financial statements.

14 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18





----------------------------------------------------------------------------------------------------------------------
Principal
Amount
USD ($)                                                                                                  Value
----------------------------------------------------------------------------------------------------------------------
                                                                                                   
                        Idaho -- 1.8%
  5,000,000             Power County Industrial Development Corp., FMC Corp.
                        Project, 6.45%, 8/1/32                                                           $   5,018,850
----------------------------------------------------------------------------------------------------------------------
                        Illinois -- 16.6%
  2,087,000(f)          Illinois Finance Authority, Clare Oaks Project, Series B,
                        4.0%, 11/15/52                                                                   $   1,711,528
  1,305,000(c)          Illinois Finance Authority, Clare Oaks Project,
                        Series C-1, 11/15/52                                                                    38,302
    261,000(c)          Illinois Finance Authority, Clare Oaks Project,
                        Series C-2, 11/15/52                                                                    77,011
    261,000(c)          Illinois Finance Authority, Clare Oaks Project,
                        Series C-3, 11/15/52                                                                    44,537
  2,000,000(d)          Illinois Finance Authority, Northwestern Memorial Hospital,
                        Series A, 6.0%, 8/15/39                                                              2,061,860
  2,500,000(d)          Illinois Finance Authority, Roosevelt University
                        Project, 6.5%, 4/1/39                                                                2,599,700
  3,865,000(d)          Illinois Finance Authority, Swedish Covenant, Series A,
                        6.0%, 8/15/38                                                                        4,045,032
  3,500,000             Illinois Finance Authority, The Admiral at the Lake Project,
                        5.25%, 5/15/42                                                                       3,318,910
  4,000,000             Illinois Finance Authority, The Admiral at the Lake Project,
                        5.5%, 5/15/54                                                                        3,896,400
  1,700,000(d)          Illinois Finance Authority, The Admiral at the Lake Project,
                        Series A, 7.625%, 5/15/25                                                            1,836,374
    600,000(d)          Illinois Finance Authority, The Admiral at the Lake Project,
                        Series A, 7.75%, 5/15/30                                                               649,260
  2,000,000(d)          Illinois Finance Authority, The Admiral at the Lake Project,
                        Series A, 8.0%, 5/15/40                                                              2,170,120
  3,200,000(d)          Illinois Finance Authority, The Admiral at the Lake Project,
                        Series A, 8.0%, 5/15/46                                                              3,472,192
  1,610,000(g)          Metropolitan Pier & Exposition Authority, McCormick Place,
                        5.65%, 6/15/22 (NATL-RE Insured)                                                     1,795,053
 13,785,000             Metropolitan Pier & Exposition Authority, McCormick Place,
                        5.65%, 6/15/22 (NATL-RE Insured)                                                    14,915,370
  1,000,000             Metropolitan Pier & Exposition Authority, McCormick Place,
                        Series B, 5.0%, 6/15/52 (ST APPROP Insured)                                          1,012,480
  1,485,000(g)          Metropolitan Pier & Exposition Authority, McCormick Place,
                        Series B, 5.65%, 6/15/22 (NATL-RE Insured)                                           1,652,953
    820,000             Southwestern Illinois Development Authority, Village of
                        Sauget Project, 5.625%, 11/1/26                                                        768,512
                                                                                                         -------------
                                                                                                         $  46,065,594
----------------------------------------------------------------------------------------------------------------------
                        Indiana -- 1.7%
    250,000             City of Carmel, Barrington Carmel Project, Series A,
                        7.0%, 11/15/32                                                                   $     245,402
    750,000             City of Carmel, Barrington Carmel Project, Series A,
                        7.125%, 11/15/42                                                                       708,533


The accompanying notes are an integral part of these financial statements.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 15



Schedule of Investments | 10/31/18 (unaudited) (continued)



----------------------------------------------------------------------------------------------------------------------
Principal
Amount
USD ($)                                                                                                  Value
----------------------------------------------------------------------------------------------------------------------
                                                                                                   
                        Indiana -- (continued)
    500,000             City of Carmel, Barrington Carmel Project, Series A,
                        7.125%, 11/15/47                                                                 $     471,755
  1,000,000             City of Evansville, Silver Birch Evansville Project,
                        5.45%, 1/1/38                                                                          957,510
  1,500,000             City of Mishawaka, Silver Birch Mishawaka Project,
                        5.375%, 1/1/38 (144A)                                                                1,455,375
  1,000,000             Indiana Finance Authority, Multipurpose Educational
                        Facilities, Avondale Meadows Academy Project,
                        5.375%, 7/1/47                                                                         944,860
                                                                                                         -------------
                                                                                                         $   4,783,435
----------------------------------------------------------------------------------------------------------------------
                        Kentucky -- 1.9%
  5,000,000(d)          Kentucky Economic Development Finance Authority,
                        Owensboro Medical Health System, Series A,
                        6.375%, 6/1/40                                                                   $   5,324,000
----------------------------------------------------------------------------------------------------------------------
                        Louisiana -- 0.8%
  2,260,000             Jefferson Parish Hospital Service District No. 2, East
                        Jefferson General Hospital, 6.375%, 7/1/41                                       $   2,201,850
----------------------------------------------------------------------------------------------------------------------
                        Maine -- 2.3%
  1,500,000             Maine Health & Higher Educational Facilities Authority,
                        Maine General Medical Center, 7.5%, 7/1/32                                       $   1,636,845
  4,480,000             Maine Turnpike Authority, Series A, 5.0%, 7/1/42                                     4,790,106
                                                                                                         -------------
                                                                                                         $   6,426,951
----------------------------------------------------------------------------------------------------------------------
                        Maryland -- 0.5%
  1,390,000             Maryland Health & Higher Educational Facilities Authority,
                        City Neighbors, Series A, 6.75%, 7/1/44                                          $   1,479,266
----------------------------------------------------------------------------------------------------------------------
                        Massachusetts -- 10.1%
  7,000,000(c)          Massachusetts Bay Transportation Authority,
                        Series A, 7/1/28                                                                 $   4,977,350
  1,550,000             Massachusetts Development Finance Agency, Harvard
                        University, Series A, 5.0%, 7/15/36                                                  1,863,937
  5,000,000             Massachusetts Development Finance Agency, Harvard
                        University, Series A, 5.0%, 7/15/40                                                  6,047,800
    947,498             Massachusetts Development Finance Agency, Linden
                        Ponds, Inc., Series A-1, 5.5%, 11/15/46                                                952,776
  1,000,000             Massachusetts Development Finance Agency, Partners
                        Healthcare System, 4.0%, 7/1/41                                                        985,290
  7,100,000             Massachusetts Development Finance Agency, WGBH
                        Foundation, Series A, 5.75%, 1/1/42 (AMBAC Insured)                                  8,997,830
    310,000             Massachusetts Educational Financing Authority, Series I,
                        6.0%, 1/1/28                                                                           317,533
  3,100,000             Massachusetts Health & Educational Facilities Authority,
                        Massachusetts Institute of Technology, Series K,
                        5.5%, 7/1/32                                                                         3,907,643
                                                                                                         -------------
                                                                                                         $  28,050,159
----------------------------------------------------------------------------------------------------------------------


The accompanying notes are an integral part of these financial statements.

16 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18





----------------------------------------------------------------------------------------------------------------------
Principal
Amount
USD ($)                                                                                                  Value
----------------------------------------------------------------------------------------------------------------------
                                                                                                   
                        Michigan -- 3.2%
  2,640,000             Michigan State University, Series A, 5.0%, 8/15/41                               $   2,878,577
  6,100,000             Michigan Tobacco Settlement Finance Authority, Series A,
                        6.0%, 6/1/48                                                                         6,003,437
                                                                                                         -------------
                                                                                                         $   8,882,014
----------------------------------------------------------------------------------------------------------------------
                        Minnesota -- 4.5%
  2,000,000             Bloomington Port Authority, Radisson Blu Mall of America,
                        9.0%, 12/1/35                                                                    $   2,185,460
  1,000,000             City of Ham Lake, DaVinci Academy, Series A, 5.0%, 7/1/47                              960,230
  2,300,000             City of Rochester, Mayo Clinic, Series B, 5.0%, 11/15/35                             2,759,632
  6,000,000(b)          State of Minnesota, Series B, 4.0%, 8/1/27                                           6,533,040
                                                                                                         -------------
                                                                                                         $  12,438,362
----------------------------------------------------------------------------------------------------------------------
                        Mississippi -- 3.4%
  3,500,000(f)          Mississippi Business Finance Corp., Chevron USA, Inc.
                        Project, Series C, 1.66%, 12/1/30                                                $   3,500,000
  5,800,000(f)          Mississippi Business Finance Corp., Chevron USA, Inc.
                        Project, Series C, 1.66%, 12/1/30                                                    5,800,000
                                                                                                         -------------
                                                                                                         $   9,300,000
----------------------------------------------------------------------------------------------------------------------
                        Montana -- 0.0%+
  1,600,000(e)          Two Rivers Authority, Inc., 7.375%, 11/1/27                                      $      67,200
----------------------------------------------------------------------------------------------------------------------
                        New Hampshire -- 0.3%
  1,000,000             New Hampshire Health & Education Facilities Authority Act,
                        Catholic Medical Centre, 3.75%, 7/1/40                                           $     920,280
----------------------------------------------------------------------------------------------------------------------
                        New Jersey -- 2.5%
  1,000,000             New Jersey Economic Development Authority, Charter
                        Marion P Thomas, 5.375%, 10/1/50 (144A)                                          $     946,800
  3,000,000             New Jersey Economic Development Authority, Continental
                        Airlines, 5.25%, 9/15/29                                                             3,214,740
  2,500,000             New Jersey Economic Development Authority, Continental
                        Airlines, 5.75%, 9/15/27                                                             2,719,725
                                                                                                         -------------
                                                                                                         $   6,881,265
----------------------------------------------------------------------------------------------------------------------
                        New Mexico -- 1.5%
  1,500,000             County of Otero, Otero County Jail Project, 9.0%, 4/1/23                         $   1,447,080
  2,960,000(f)          County of Otero, Otero County Jail Project, 9.0%, 4/1/28                             2,749,041
                                                                                                         -------------
                                                                                                         $   4,196,121
----------------------------------------------------------------------------------------------------------------------
                        New York -- 8.6%
  2,000,000(d)          Hempstead Local Development Corp., Molloy College
                        Project, 5.75%, 7/1/39                                                           $   2,051,040
  1,000,000(d)          New York State Dormitory Authority, Orange Medical Center,
                        6.125%, 12/1/29                                                                      1,003,520
  8,000,000             New York State Dormitory Authority, Series A, 4.0%, 7/1/41                           8,076,400
  7,500,000             New York State Dormitory Authority, Series C, 5.0%, 3/15/39                          8,187,975


The accompanying notes are an integral part of these financial statements.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 17



Schedule of Investments | 10/31/18 (unaudited) (continued)



----------------------------------------------------------------------------------------------------------------------
Principal
Amount
USD ($)                                                                                                  Value
----------------------------------------------------------------------------------------------------------------------
                                                                                                   
                        New York -- (continued)
  1,500,000             New York State Dormitory Authority, Trustees of Columbia
                        University, 5.0%, 10/1/45                                                        $   1,845,165
  2,410,177             Westchester County Healthcare Corp., Series A,
                        5.0%, 11/1/44                                                                        2,511,067
                                                                                                         -------------
                                                                                                         $  23,675,167
----------------------------------------------------------------------------------------------------------------------
                        North Carolina -- 2.8%
  3,300,000(f)          Charlotte-Mecklenburg Hospital Authority, North Carolina
                        Health Care System Revenue, 1.68%, 1/15/38                                       $   3,300,000
  4,225,000(c)(f)       Tender Option Bond Trust Receipts/Certificates, RIB,
                        Series 2018, 1/1/38 (144A)                                                           4,468,444
                                                                                                         -------------
                                                                                                         $   7,768,444
----------------------------------------------------------------------------------------------------------------------
                        North Dakota -- 1.0%
  2,525,000(d)          County of Burleigh, St. Alexius Medical Center,
                        5.0%, 7/1/38                                                                     $   2,751,088
----------------------------------------------------------------------------------------------------------------------
                        Ohio -- 5.5%
  1,325,000             Buckeye Tobacco Settlement Financing Authority,
                        Asset-Backed, Series A-2, 5.75%, 6/1/34                                          $   1,275,856
  2,500,000             Buckeye Tobacco Settlement Financing Authority,
                        Asset-Backed, Series A-2, 5.875%, 6/1/47                                             2,427,475
  1,700,000             Buckeye Tobacco Settlement Financing Authority,
                        Asset-Backed, Series A-2, 6.0%, 6/1/42                                               1,672,528
  6,000,000             Buckeye Tobacco Settlement Financing Authority,
                        Asset-Backed, Series A-2, 6.5%, 6/1/47                                               6,064,500
  1,000,000             Ohio Housing Finance Agency, Sanctuary Springboro
                        Project, 5.45%, 1/1/38 (144A)                                                          978,980
  2,500,000(b)(d)       State of Ohio, Common Schools, Series B, 5.0%, 6/15/29                               2,735,800
                                                                                                         -------------
                                                                                                         $  15,155,139
----------------------------------------------------------------------------------------------------------------------
                        Oregon -- 2.4%
  1,000,000             Oregon Health & Science University, Series A, 5.0%, 7/1/42                       $   1,100,230
  5,190,000             Oregon Health & Science University, Series E, 5.0%, 7/1/32                           5,607,328
                                                                                                         -------------
                                                                                                         $   6,707,558
----------------------------------------------------------------------------------------------------------------------
                        Pennsylvania -- 5.2%
  3,000,000             Geisinger Authority, Geisinger Health System, series A-1,
                        5.0%, 2/15/45                                                                    $   3,244,830
  1,280,000(e)          Langhorne Manor Borough Higher Education Authority,
                        Lower Bucks Hospital, 7.35%, 7/1/22                                                    537,600
  5,000,000             Pennsylvania Economic Development Financing Authority,
                        USG Corp. Project, 6.0%, 6/1/31                                                      4,904,650
    500,000             Philadelphia Authority for Industrial Development,
                        Greater Philadelphia Health Action, Inc., Project, Series A,
                        6.625%, 6/1/50                                                                         511,575
  2,000,000             Philadelphia Authority for Industrial Development,
                        Nueva Esperanze, Inc., 8.2%, 12/1/43                                                 2,182,760


The accompanying notes are an integral part of these financial statements.

18 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18





----------------------------------------------------------------------------------------------------------------------
Principal
Amount
USD ($)                                                                                                  Value
----------------------------------------------------------------------------------------------------------------------
                                                                                                   
                        Pennsylvania -- (continued)
  1,000,000             Philadelphia Authority for Industrial Development,
                        Performing Arts Charter School Project, 6.5%,
                        6/15/33 (144A)                                                                   $   1,035,110
  2,000,000             Philadelphia Authority for Industrial Development,
                        Performing Arts Charter School Project, 6.75%,
                        6/15/43 (144A)                                                                       2,068,440
                                                                                                         -------------
                                                                                                         $  14,484,965
----------------------------------------------------------------------------------------------------------------------
                        Puerto Rico -- 1.3%
  6,255,000(b)(e)       Commonwealth of Puerto Rico, Series A, 8.0%, 7/1/35                              $   3,690,450
----------------------------------------------------------------------------------------------------------------------
                        Rhode Island -- 1.7%
  5,900,000(e)          Central Falls Detention Facility Corp., 7.25%, 7/15/35                           $   1,062,000
  2,000,000             Rhode Island Health & Educational Building Corp., Brown
                        University, Series A, 4.0%, 9/1/37                                                   2,040,220
  1,500,000(d)          Rhode Island Health & Educational Building Corp.,
                        Tockwatten Home Issue, 8.375%, 1/1/46                                                1,692,225
                                                                                                         -------------
                                                                                                         $   4,794,445
----------------------------------------------------------------------------------------------------------------------
                        Texas -- 10.6%
  1,000,000             Arlington Higher Education Finance Corp., Universal
                        Academy, Series A, 7.0%, 3/1/34                                                  $   1,016,710
  2,500,000(d)          Central Texas Regional Mobility Authority, Sub Lien,
                        6.75%, 1/1/41                                                                        2,731,750
  1,490,000(b)          County of Harris, Series A, 5.0%, 10/1/26                                            1,701,759
  5,000,000(b)          Goose Creek Consolidated Independent School District,
                        Series C, 4.0%, 2/15/26 (PSF-GTD Insured)                                            5,320,600
    725,078(e)          Gulf Coast Industrial Development Authority, Microgy
                        Holdings Project, 7.0%, 12/1/36                                                              7
  4,900,000(f)          Harris County Health Facilities Development Corp., The
                        Methodist Hospital System, Series A-2, 1.7%, 12/1/41                                 4,900,000
  3,785,000             North Texas Tollway Authority, Series A, 5.0%, 1/1/35                                4,108,088
  1,500,000(d)          Red River Health Facilities Development Corp., MRC
                        Crestview, Series A, 8.0%, 11/15/41                                                  1,745,490
  3,960,000+(e)         Sanger Industrial Development Corp., Texas Pellets Project,
                        Series B, 8.0%, 7/1/38                                                               1,520,640
  1,000,000(e)          Tarrant County Cultural Education Facilities Finance Corp.,
                        Mirador Project, Series A, 4.875%, 11/15/48                                            679,460
  1,000,000             Tarrant County Cultural Education Facilities Finance Corp.,
                        Mirador Project, Series A, 5.0%, 11/15/55                                              678,180
  2,000,000(d)          Tarrant County Cultural Education Facilities Finance Corp.,
                        MRC Crestview Project, 8.0%, 11/15/34                                                2,225,040
  2,500,000(d)          Travis County Health Facilities Development Corp., Longhorn
                        Village Project, 7.125%, 1/1/46                                                      2,751,975
                                                                                                         -------------
                                                                                                         $  29,379,699
----------------------------------------------------------------------------------------------------------------------
                        Utah -- 0.4%
  1,000,000             Salt Lake City Corp., Airport Revenue, Series B,
                        5.0%, 7/1/35                                                                     $   1,108,860
----------------------------------------------------------------------------------------------------------------------


The accompanying notes are an integral part of these financial statements.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 19



Schedule of Investments | 10/31/18 (unaudited) (continued)



-----------------------------------------------------------------------------------------------------------------------
Principal
Amount
USD ($)                                                                                                  Value
-----------------------------------------------------------------------------------------------------------------------
                                                                                                   
                        Virginia -- 4.9%
  2,200,000(b)          County of Arlington, 4.0%, 8/15/35                                               $   2,280,806
  1,415,000(b)          County of Fairfax, Series A, 4.0%, 10/1/33
                        (ST AID WITHHLDG Insured)                                                            1,496,815
  5,000,000             University of Virginia, Series A, 5.0%, 4/1/42                                       5,608,200
  4,000,000             Upper Occoquan Sewage Authority, 4.0%, 7/1/41                                        4,086,760
                                                                                                         --------------
                                                                                                         $  13,472,581
-----------------------------------------------------------------------------------------------------------------------
                        Washington -- 11.2%
  3,745,000             City of Seattle, Water System Revenue, 4.0%, 8/1/32                              $   3,905,249
  2,500,000(b)          King County, Issaquah School District No. 411, 4.0%,
                        12/1/31 (SCH BD GTY Insured)                                                         2,623,325
 14,315,000(b)(c)       State of Washington, Motor Vehicle Sales Tax, Series C,
                        6/1/22 (NATL Insured)                                                               13,101,231
  3,285,000(c)(f)       Tender Option Bond Trust Receipts/Certificates, RIB,
                        Series 2018, 1/1/45 (144A)                                                           3,362,559
  2,500,000             University of Washington, Series B, 5.0%, 6/1/29                                     2,838,050
  3,795,000(d)          Washington State Health Care Facilities Authority, Fred
                        Hutchinson Cancer Research Center, Series A, 6.0%, 1/1/33                            3,893,480
  1,150,000             Washington State Housing Finance Commission, Mirabella
                        Project, Series A, 6.75%, 10/1/47 (144A)                                             1,227,406
                                                                                                         --------------
                                                                                                         $  30,951,300
-----------------------------------------------------------------------------------------------------------------------
                        West Virginia -- 0.5%
  2,000,000(e)          City of Philippi, Alderson-Broaddus College, Inc., Series A,
                        7.75%, 10/1/44                                                                   $   1,392,000
-----------------------------------------------------------------------------------------------------------------------
                        Wisconsin -- 5.3%
  5,000,000             Public Finance Authority, Glenridge Palmer Ranch, Series A,
                        8.25%, 6/1/46 (144A)                                                             $   5,628,550
    750,000             Public Finance Authority, Roseman University Health
                        Sciences Project, 5.875%, 4/1/45                                                       788,955
  1,000,000             Public Finance Authority, SearStone CCRC Project, Series A,
                        5.3%, 6/1/47                                                                           937,170
  1,490,000(d)          Public Finance Authority, SearStone CCRC Project, Series A,
                        8.625%, 6/1/47                                                                       1,783,798
  5,000,000             Wisconsin Department of Transportation, Series A,
                        5.0%, 7/1/28                                                                         5,622,400
                                                                                                         --------------
                                                                                                         $  14,760,873
-----------------------------------------------------------------------------------------------------------------------
                        TOTAL TAX EXEMPT OBLIGATIONS
                        (Cost $391,397,665)                                                              $ 393,991,434
-----------------------------------------------------------------------------------------------------------------------
                        TOTAL INVESTMENTS IN UNAFFILIATED ISSUERS -- 143.1%
                        (Cost $393,919,665)                                                              $ 396,513,434
-----------------------------------------------------------------------------------------------------------------------
                        OTHER ASSETS AND LIABILITIES -- 2.0%                                             $   5,586,096
-----------------------------------------------------------------------------------------------------------------------
                        VARIABLE RATE MUNIFUND TERM PREFERRED SHARES
                        AT REDEMPTION VALUE -- (45.1)%                                                   $(125,000,084)
-----------------------------------------------------------------------------------------------------------------------
                        NET ASSETS APPLICABLE TO COMMON
                        SHAREOWNERS -- 100.0%                                                            $ 277,099,446
=======================================================================================================================


The accompanying notes are an integral part of these financial statements.

20 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



RIB      Residual Interest Bond is purchased in a secondary market. The interest
         rate is subject to change periodically and inversely based upon
         prevailing market rates. The interest rate shown is the rate at October
         31, 2018.

(144A)   Security is exempt from registration under Rule 144A of the Securities
         Act of 1933. Such securities may be resold normally to qualified
         institutional buyers in a transaction exempt from registration. At
         October 31, 2018, the value of these securities amounted to
         $33,394,144, or 12.1% of net assets applicable to common shareowners.

+        Amount rounds to less than 0.1%.

+        Securities that used significant unobservable inputs to determine their
         value.

(a)      Consists of Revenue Bonds unless otherwise indicated.

(b)      Represents a General Obligation Bond.

(c)      Security issued with a zero coupon. Income is recognized through
         accretion of discount.

(d)      Prerefunded bonds have been collateralized by U.S. Treasury or U.S.
         Government Agency securities which are held in escrow to pay interest
         and principal on the tax exempt issue and to retire the bonds in full
         at the earliest refunding date.

(e)      Security is in default.

(f)      The interest rate is subject to change periodically. The interest rate
         and/or reference index and spread shown at October 31, 2018.

(g)      Escrow to maturity.

Purchases and sales of securities (excluding temporary cash investments) for
the six months ended October 31, 2018, aggregated $42,050,137 and $41,500,052,
respectively.

The Trust is permitted to engage in purchase and sale transactions ("cross
trades") with certain funds and accounts for which Amundi Pioneer Asset
Management, Inc., (the "Adviser"), serves as the investment adviser, as set
forth in Rule 17a-7 under the Investment Company Act of 1940, pursuant to
procedures adopted by the Board of Trustees. Under these procedures, cross
trades are effected at current market prices. During the six months ended
October 31, 2018, the Trust engaged in purchases of 2,200,497 and sales of $0
pursuant to these procedures, which resulted in a net realized gain/loss of
$0.

At October 31, 2018, the net unrealized appreciation on investments based on
cost for federal tax purposes of $393,499,972 was as follows:



                                                                                  
         Aggregate gross unrealized appreciation for all investments in which
          there is an excess of value over tax cost                                  $ 22,551,037
         Aggregate gross unrealized depreciation for all investments in which
          there is an excess of tax cost over value                                   (19,537,575)
                                                                                     ------------
         Net unrealized appreciation                                                 $  3,013,462
                                                                                     ============


Various inputs are used in determining the value of the Trust's investments.
These inputs are summarized in the three broad levels below.

  Level 1 - quoted prices in active markets for identical securities.

  Level 2 - other significant observable inputs (including quoted prices for
            similar securities, interest rates, prepayment speeds, credit risks,
            etc.). See Notes to Financial Statements -- Note 1A.

  Level 3 - significant unobservable inputs (including the Trust's own
            assumptions in determining fair value of investments). See Notes to
            Financial Statements -- Note 1A.

The accompanying notes are an integral part of these financial statements.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 21



Schedule of Investments | 10/31/18 (unaudited) (continued)

The following is a summary of the inputs used as of October 31, 2018, in
valuing the Trust's investments.



---------------------------------------------------------------------------------------------------------
                                            Level 1      Level 2           Level 3         Total
---------------------------------------------------------------------------------------------------------
                                                                               
Debtor in Possession Financing              $   --       $  2,522,000      $       --      $  2,522,000
Tax Exempt Obligations
  Colorado                                      --          1,877,010       1,966,631         3,843,641
  Texas                                         --         27,859,059       1,520,640        29,379,699
  All Other Tax Exempt Obligations              --        360,768,094              --       360,768,094
---------------------------------------------------------------------------------------------------------
Total Investments in Securities             $   --       $393,026,163      $3,487,271      $396,513,434
=========================================================================================================


The following is a reconciliation of assets valued using significant
unobservable inputs (Level 3):



---------------------------------------------------------------------------------------------------------
                                                                                   Tax Exempt Obligations
---------------------------------------------------------------------------------------------------------
                                                                                           
Balance as of 4/30/18                                                                         $1,485,000
Realized gain (loss)1                                                                                 --
Change in unrealized appreciation (depreciation)2                                                 84,917
Accrued discounts/premiums                                                                       (10,283)
Purchases                                                                                      1,927,637
Sales                                                                                                 --
Transfers in to Level 3*                                                                              --
Transfers out of Level 3*                                                                              0
---------------------------------------------------------------------------------------------------------
Balance as of 10/31/18                                                                        $3,487,271
=========================================================================================================


1     Realized gain (loss) on these securities is included in the realized gain
      (loss) from investments on the Statement of Operations.

2     Unrealized appreciation (depreciation) on these securities is included in
      the change in unrealized appreciation (depreciation) from investments on
      the Statement of Operations.

*     Transfers are calculated on the beginning of period values. During the six
      months ended October 31, 2018, an investment having a value of
      $(1,485,000) was transferred out of Level 3 to Level 2, as there was
      observable input available to determine its value. There were no other
      transfers between Levels 1, 2 and 3.



                                                                                               
Net change in unrealized appreciation (depreciation) of Level 3 investments still held
and considered Level 3 at October 31, 2018:                                                       $84,917
                                                                                                  -------


The accompanying notes are an integral part of these financial statements.

22 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



Statement of Assets and Liabilities | 10/31/18 (unaudited)



                                                                                       
ASSETS:
  Investments in unaffiliated issuers, at value (cost $393,919,665)                       $396,513,434
  Receivables --
     Investment securities sold                                                                154,565
     Interest                                                                                6,107,160
  Other assets                                                                                 229,256
-------------------------------------------------------------------------------------------------------
       Total assets                                                                       $403,004,415
=======================================================================================================
LIABILITIES:
  Due to Custodian                                                                        $    754,776
  Payables --
     Distributions                                                                                  25
     Professional fees                                                                          30,203
     Transfer agent fees                                                                         1,045
     Administrative fees                                                                        24,437
     Shareowner communications expense                                                           1,335
     Trustees' fees                                                                              2,383
     Custodian fees                                                                                980
     Printing expense                                                                            5,348
     Pricing fees                                                                                2,783
  Due to affiliates                                                                             35,542
  Accrued expenses                                                                              46,028
-------------------------------------------------------------------------------------------------------
       Total liabilities                                                                  $    904,885
=======================================================================================================
Variable Rate MuniFund Term Preferred Shares, net of deferred offering costs:
  $100,000 liquidation value per share applicable to 1,250 shares,
     Including dividends payable of $84                                                   $125,000,084
-------------------------------------------------------------------------------------------------------
NET ASSETS APPLICABLE TO COMMON SHAREOWNERS:
  Paid-in capital                                                                         $300,996,046
  Distributions in excess of earnings                                                      (23,896,600)
-------------------------------------------------------------------------------------------------------
       Net assets applicable to common shareowners                                        $277,099,446
=======================================================================================================
NET ASSET VALUE PER COMMON SHARE:
  No par value
     Based on $277,099,446/22,771,349 common shares                                       $      12.17
=======================================================================================================


The accompanying notes are an integral part of these financial statements.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 23



Statement of Operations (unaudited)

FOR THE SIX MONTHS ENDED 10/31/18



                                                                                     
INVESTMENT INCOME:
  Interest from unaffiliated issuers                                    $ 9,642,927
-------------------------------------------------------------------------------------------------------
     Total investment income                                                               $ 9,642,927
-------------------------------------------------------------------------------------------------------
EXPENSES:
  Management fees                                                       $ 1,237,990
  Administrative expense                                                     68,912
  Transfer agent fees                                                         4,256
  Shareowner communications expense                                          16,038
  Custodian fees                                                              1,645
  Registration fees                                                           7,360
  Professional fees                                                          61,147
  Printing expense                                                            6,058
  Pricing fees                                                               17,401
  Trustees' fees                                                              9,159
  Insurance expense                                                           1,173
  Miscellaneous                                                              35,168
-------------------------------------------------------------------------------------------------------
     Total expenses                                                                        $ 1,466,307
-------------------------------------------------------------------------------------------------------
       Net investment income                                                               $ 8,176,620
-------------------------------------------------------------------------------------------------------
REALIZED AND UNREALIZED GAIN (LOSS) ON INVESTMENTS:
  Net realized gain (loss) on:
     Investments in unaffiliated issuers                                $  (333,246)
  Change in net unrealized appreciation (depreciation) on:
     Investments in unaffiliated issuers                                 (6,527,932)
-------------------------------------------------------------------------------------------------------
       Net realized and unrealized gain (loss) on investments                              $(6,861,178)
-------------------------------------------------------------------------------------------------------
DISTRIBUTIONS TO PREFERRED SHAREOWNERS:                                                    $(1,639,075)
-------------------------------------------------------------------------------------------------------
  Net decrease in net assets resulting from operations                                     $  (323,633)
=======================================================================================================


The accompanying notes are an integral part of these financial statements.

24 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



Statements of Changes in Net Assets



-----------------------------------------------------------------------------------------------------
                                                                  Six Months
                                                                  Ended                 Year
                                                                  10/31/18              Ended
                                                                  (unaudited)           4/30/18
-----------------------------------------------------------------------------------------------------
                                                                                  
FROM OPERATIONS:
Net investment income (loss)                                      $  8,176,620          $ 17,856,773
Net realized gain (loss) on investments                               (333,246)          (12,146,048)
Change in net unrealized appreciation (depreciation)
  on investments                                                    (6,527,932)            5,201,392
Distributions to preferred shareowners                              (1,639,075)           (2,052,256)
-----------------------------------------------------------------------------------------------------
     Net increase (decrease) in net assets resulting
       from operations                                            $   (323,633)         $  8,859,861
-----------------------------------------------------------------------------------------------------
DISTRIBUTIONS TO COMMON SHAREOWNERS:
($0.32 and $0.62 per share, respectively)                         $ (7,172,975)         $(14,004,380)
-----------------------------------------------------------------------------------------------------
       Total distributions to common shareowners                  $ (7,172,975)         $(14,004,380)
-----------------------------------------------------------------------------------------------------
     Net decrease in net assets applicable to common
       shareowners                                                $ (7,496,608)         $ (5,144,519)
-----------------------------------------------------------------------------------------------------
NET ASSETS APPLICABLE TO COMMON SHAREOWNERS:
Beginning of period                                                284,596,054           289,740,573
-----------------------------------------------------------------------------------------------------
End of period                                                     $277,099,446          $284,596,054
=====================================================================================================


The accompanying notes are an integral part of these financial statements.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 25



Financial Highlights



----------------------------------------------------------------------------------------------------------------------------------
                                                              Six Months
                                                              Ended         Year      Year       Year        Year        Year
                                                              10/31/18      Ended     Ended      Ended       Ended       Ended
                                                              (unaudited)   4/30/18   4/30/17*   4/30/16*    4/30/15*    4/30/14
----------------------------------------------------------------------------------------------------------------------------------
                                                                                                       
Per Share Operating Performance
Net asset value, beginning of period                          $  12.50      $  12.72  $  13.49   $  13.31    $  13.33    $  14.72
----------------------------------------------------------------------------------------------------------------------------------
Increase (decrease) from investment operations: (a)
  Net investment income (loss)                                $   0.36      $   0.78  $   0.73   $   0.83    $   0.91    $   1.05
  Net realized and unrealized gain (loss) on investments         (0.30)        (0.29)    (0.76)      0.20        0.16       (1.29)
----------------------------------------------------------------------------------------------------------------------------------
Distribution to preferred shareowners from:
  Net investment income                                       $  (0.07)     $  (0.09) $  (0.05)  $  (0.01)   $  (0.01)   $  (0.01)
----------------------------------------------------------------------------------------------------------------------------------
Net increase (decrease) from investment operations            $  (0.01)     $   0.40  $  (0.08)  $   1.02    $   1.06    $  (0.25)
----------------------------------------------------------------------------------------------------------------------------------
Distributions to common shareowners from:
  Net investment income and previously undistributed
    net investment income                                     $  (0.32)     $  (0.62) $  (0.69)  $  (0.84)** $  (1.08)** $  (1.14)**
----------------------------------------------------------------------------------------------------------------------------------
Net increase (decrease) in net asset value                    $  (0.33)     $  (0.22) $  (0.77)  $   0.18    $  (0.02)   $  (1.39)
----------------------------------------------------------------------------------------------------------------------------------
Net asset value, end of period                                $  12.17      $  12.50  $  12.72   $  13.49    $  13.31    $  13.33
----------------------------------------------------------------------------------------------------------------------------------
Market value, end of period                                   $  10.78      $  11.25  $  11.75   $  14.07    $  14.75    $  14.90
==================================================================================================================================
Total return at net asset value (b)                               0.09%(c)      3.53%    (0.45)%     8.12%       7.76%      (1.57)%
Total return at market value (b)                                 (1.50)%(c)     0.87%   (11.83)%     1.75%       6.84%       1.10%
Ratios to average net assets of common shareowners:
  Total expenses (d)                                              1.02%(e)      1.01%     1.00%      1.05%       1.03%       1.04%
  Net investment income before preferred share distributions      5.71%(e)      6.14%     5.54%      6.24%       6.73%       7.89%
  Preferred share distributions                                   1.15%(e)      0.71%     0.38%      0.10%       0.04%       0.05%
  Net investment income available to common shareowners           4.56%(e)      5.44%     5.16%      6.14%       6.69%       7.84%
Portfolio turnover rate                                             10%(c)        20%       19%         9%         14%         19%
Net assets of common shareowners, end of period
 (in thousands)                                               $277,099      $284,596  $289,741   $307,027    $302,718    $301,872


The accompanying notes are an integral part of these financial statements.

26 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18





------------------------------------------------------------------------------------------------------------------------------------
                                                                       Six Months
                                                                       Ended        Year      Year      Year      Year      Year
                                                                       10/31/18     Ended     Ended     Ended     Ended     Ended
                                                                       (unaudited)  4/30/18   4/30/17*  4/30/16*  4/30/15*  4/30/14
------------------------------------------------------------------------------------------------------------------------------------
                                                                                                          
Preferred shares outstanding (in thousands) (f)(g)                     $125,000     $125,000  $101,000  $101,000  $101,000  $101,000
Asset coverage per preferred share, end of period                      $321,680     $327,672  $ 96,723  $100,998  $ 99,930  $ 99,721
Average market value per preferred share (h)                           $100,000     $100,000  $ 25,000  $ 25,000  $ 25,000  $ 25,000
Liquidation value, including dividends payable, per preferred share    $100,000     $ 99,996  $ 25,006  $ 25,001  $ 25,000  $ 25,001
====================================================================================================================================


*     The Trust was audited by an independent registered public accounting firm
      other than Ernst & Young LLP.

**    The amount of distributions made to shareowners during the year were in
      excess of the net investment income earned by the Trust during the year.
      The Trust has accumulated undistributed net investment income which is
      part of the Trust's NAV. A portion of the accumulated net investment
      income was distributed to shareowners during the year.

(a)   The per common share data presented above is based upon the average common
      shares outstanding for the periods presented.

(b)   Total investment return is calculated assuming a purchase of common shares
      at the current net asset value or market value on the first day and a sale
      at the current net asset value or market value on the last day of the
      periods reported. Dividends and distributions, if any, are assumed for
      purposes of this calculation to be reinvested at prices obtained under the
      Trust's dividend reinvestment plan. Total investment return does not
      reflect brokerage commissions. Past performance is not a guarantee of
      future results.

(c)   Not annualized.

(d)   Expense ratios do not reflect the effect of distribution payments to
      preferred shareowners.

(e)   Annualized.

(f)   Prior to February 9, 2018 there were 4,040 Auction Preferred Shares
      ("APS") outstanding with a liquidation preference of $25,000 per share.
      The Trust redeemed all 2,000 outstanding Series A APS on February 14, 2018
      and all 2,040 outstanding Series B APS on February 15, 2018.

(g)   The Trust issued 1,250 Variable Rate MuniFund Term Preferred Shares, with
      a liquidation preference of $100,000 per share, on February 9, 2018.

(h)   Market value is redemption value without an active market.

The accompanying notes are an integral part of these financial statements.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 27



Notes to Financial Statements | 10/31/18 (unaudited)

1. Organization and Significant Accounting Policies

Pioneer Municipal High Income Trust (the "Trust") was organized as a Delaware
statutory trust on March 13, 2003. Prior to commencing operations on July 21,
2003, the Trust had no operations other than matters relating to its
organization and registration as a diversified, closed-end management
investment company under the Investment Company Act of 1940, as amended. The
investment objective of the Trust is to seek a high level of current income
exempt from regular federal income tax, and the Trust may, as a secondary
objective, also seek capital appreciation to the extent that it is consistent
with its primary investment objective.

Amundi Pioneer Asset Management, Inc., an indirect wholly owned subsidiary of
Amundi and Amundi's wholly owned subsidiary, Amundi USA, Inc., serves as the
Trust's investment adviser (the "Adviser"). Amundi Pioneer Distributor, Inc.,
an affiliate of Amundi Pioneer Asset Management, Inc., serves as the Trust's
distributor (the "Distributor").

In August 2018, the SEC released a Disclosure Update and Simplification Final
Rule. The Final Rule amends Regulation S-X disclosures requirements to conform
them to U.S. Generally Accepted Accounting Principles ("U.S. GAAP") for
investment companies. The Trust's financial statements were prepared in
compliance with the new amendments to Regulation S-X.

The Trust is an investment company and follows investment company accounting
and reporting guidance under U.S. GAAP. U.S. GAAP requires the management of
the Trust to make estimates and assumptions that affect the reported amounts of
assets and liabilities, the disclosure of contingent assets and liabilities at
the date of the financial statements, and the reported amounts of income,
expenses and gain or loss on investments during the reporting period. Actual
results could differ from those estimates.

The following is a summary of significant accounting policies followed by the
Trust in the preparation of its financial statements:

A.    Security Valuation

      The net asset value of the Trust is computed once daily, on each day the
      New York Stock Exchange ("NYSE") is open, as of the close of regular
      trading on the NYSE.

      Fixed-income securities are valued by using prices supplied by independent
      pricing services, which consider such factors as market prices, market
      events, quotations from one or more brokers, Treasury spreads, yields,
      maturities and ratings, or may use a pricing matrix or other fair value
      methods or techniques

28 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



      to provide an estimated value of the security or instrument. A pricing
      matrix is a means of valuing a debt security on the basis of current
      market prices for other debt securities, historical trading patterns in
      the market for fixed-income securities and/or other factors. Non-U.S. debt
      securities that are listed on an exchange will be valued at the bid price
      obtained from an independent third party pricing service. When independent
      third party pricing services are unable to supply prices, or when prices
      or market quotations are considered to be unreliable, the value of that
      security may be determined using quotations from one or more
      broker-dealers.

      Cash may include overnight time deposits at approved financial
      institutions.

      Securities for which independent pricing services or broker-dealers are
      unable to supply prices or for which market prices and/or quotations are
      not readily available or are considered to be unreliable are valued by a
      fair valuation team comprised of certain personnel of the Adviser pursuant
      to procedures adopted by the Trust's Board of Trustees. The Adviser's fair
      valuation team uses fair value methods approved by the Valuation Committee
      of the Board of Trustees. The Adviser's fair valuation team is responsible
      for monitoring developments that may impact fair valued securities and for
      discussing and assessing fair values on an ongoing basis, and at least
      quarterly, with the Valuation Committee of the Board of Trustees.

      Inputs used when applying fair value methods to value a security may
      include credit ratings, the financial condition of the company, current
      market conditions and comparable securities. The Trust may use fair value
      methods if it is determined that a significant event has occurred after
      the close of the exchange or market on which the security trades and prior
      to the determination of the Trust's net asset value. Examples of a
      significant event might include political or economic news, corporate
      restructurings, natural disasters, terrorist activity or trading halts.
      Thus, the valuation of the Trust's securities may differ significantly
      from exchange prices, and such differences could be material.

      At October 31, 2018, no securities were valued using fair value methods
      (other than securities valued using prices supplied by independent pricing
      services, broker-dealers or using a third party insurance industry pricing
      model).

B.    Investment Income and Transactions

      Interest income, including interest on income-bearing cash accounts, is
      recorded on the accrual basis. Dividend and interest income are reported
      net of unrecoverable foreign taxes withheld at the applicable country
      rates and net of income accrued on defaulted securities.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 29



      Discounts and premiums on purchase prices of debt securities are accreted
      or amortized, respectively, daily, into interest income on an effective
      yield to maturity basis with a corresponding increase or decrease in the
      cost basis of the security. Premiums and discounts related to certain
      mortgage-backed securities are amortized or accreted in proportion to the
      monthly paydowns.

      Interest and dividend income payable by delivery of additional shares is
      reclassified as PIK (payment-in-kind) income upon receipt and is included
      in interest and dividend income, respectively.

      Security transactions are recorded as of trade date. Gains and losses on
      sales of investments are calculated on the identified cost method for both
      financial reporting and federal income tax purposes.

C.    Federal Income Taxes

      It is the Trust's policy to comply with the requirements of the Internal
      Revenue Code applicable to regulated investment companies and to
      distribute all of its net taxable income and net realized capital gains,
      if any, to its shareowners. Therefore, no provision for federal income
      taxes is required. As of April 30, 2018, the Trust did not accrue any
      interest or penalties with respect to uncertain tax positions, which, if
      applicable, would be recorded as an income tax expense on the Statement of
      Operations. Tax returns filed within the prior three years remain subject
      to examination by federal and state tax authorities.

      The amount and character of income and capital gain distributions to
      shareowners are determined in accordance with federal income tax rules,
      which may differ from U.S. GAAP. Distributions in excess of net investment
      income or net realized gains are temporary over distributions for
      financial statement purposes resulting from differences in the recognition
      or classification of income or distributions for financial statement and
      tax purposes. Capital accounts within the financial statements are
      adjusted for permanent book/tax differences to reflect tax character, but
      are not adjusted for temporary differences.

      The tax character of current year distributions payable will be determined
      at the end of the current taxable year. The tax character of distributions
      paid during the year ended April 30, 2018 was as follows:



      --------------------------------------------------------------------------
                                                                            2018
      --------------------------------------------------------------------------
                                                                  
      Distributions paid from:
      Tax Exempt Distributions                                       $15,643,034
      Ordinary income                                                    413,602
      --------------------------------------------------------------------------
          Total                                                      $16,056,636
      ==========================================================================


30 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



      The following shows the components of distributable earnings (losses) on a
      federal income tax basis at April 30, 2018:



      --------------------------------------------------------------------------
                                                                           2018
      --------------------------------------------------------------------------
                                                                
      Distributable earnings:
      Undistributed ordinary income                                $    415,696
      Capital loss carryforward                                     (29,043,444)
      Other book/tax temporary differences                              419,668
      Undistributed tax-exempt income                                 2,686,387
      Unrealized appreciation                                         9,121,701
      --------------------------------------------------------------------------
          Total                                                    $(16,399,992)
      ==========================================================================


      The difference between book-basis and tax-basis unrealized
      appreciation/depreciation is primarily attributable to the book/tax
      differences in the accrual of income on securities in default, the
      difference between book and tax amortization methods and discounts on
      fixed income securities.

D.    Automatic Dividend Reinvestment Plan

      All shareowners whose shares are registered in their own names
      automatically participate in the Automatic Dividend Reinvestment Plan (the
      "Plan"), under which participants receive all dividends and capital gain
      distributions (collectively, dividends) in full and fractional shares of
      the Trust in lieu of cash. Shareowners may elect not to participate in the
      Plan. Shareowners not participating in the Plan receive all dividends and
      capital gain distributions in cash. Participation in the Plan is
      completely voluntary and may be terminated or resumed at any time without
      penalty by notifying American Stock Transfer & Trust Company, the agent
      for shareowners in administering the Plan (the "Plan Agent"), in writing
      prior to any dividend record date; otherwise such termination or
      resumption will be effective with respect to any subsequently declared
      dividend or other distribution.

      If a shareowner's shares are held in the name of a brokerage firm, bank or
      other nominee, the shareowner can ask the firm or nominee to participate
      in the Plan on the shareowner's behalf. If the firm or nominee does not
      offer the Plan, dividends will be paid in cash to the shareowner of
      record. A firm or nominee may reinvest a shareowner's cash dividends in
      shares of the Trust on terms that differ from the terms of the Plan.

      Whenever the Trust declares a dividend on shares payable in cash,
      participants in the Plan will receive the equivalent in shares acquired by
      the Plan Agent either (i) through receipt of additional unissued but
      authorized shares from the Trust or (ii) by purchase of outstanding shares
      on the New York Stock Exchange or elsewhere. If, on the payment date for
      any dividend, the net asset value per share is equal to or less than the
      market price per share

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 31



      plus estimated brokerage trading fees (market premium), the Plan Agent
      will invest the dividend amount in newly issued shares. The number of
      newly issued shares to be credited to each account will be determined by
      dividing the dollar amount of the dividend by the net asset value per
      share on the date the shares are issued, provided that the maximum
      discount from the then current market price per share on the date of
      issuance does not exceed 5%. If, on the payment date for any dividend, the
      net asset value per share is greater than the market value (market
      discount), the Plan Agent will invest the dividend amount in shares
      acquired in open-market purchases. There are no brokerage charges with
      respect to newly issued shares. However, each participant will pay a pro
      rata share of brokerage trading fees incurred with respect to the Plan
      Agent's open-market purchases. Participating in the Plan does not relieve
      shareowners from any federal, state or local taxes which may be due on
      dividends paid in any taxable year. Shareowners holding Plan shares in a
      brokerage account may be able to transfer the shares to another broker and
      continue to participate in the Plan.

E.    Risks

      The value of securities held by the Trust may go up or down, sometimes
      rapidly or unpredictably, due to general market conditions, such as real
      or perceived adverse economic, political or regulatory conditions,
      inflation, changes in interest rates, lack of liquidity in the bond
      markets or adverse investor sentiment. In the past several years,
      financial markets have experienced increased volatility, depressed
      valuations, decreased liquidity and heightened uncertainty. These
      conditions may continue, recur, worsen or spread.

      Interest rates in the U.S. recently have been historically low, but have
      begun to rise and the Trust faces a heightened risk that interest rates
      may continue to rise. A general rise in interest rates could adversely
      affect the price and liquidity of fixed-income securities and could also
      result in increased redemptions from the Trust.

      The municipal bond market can be susceptible to unusual volatility,
      particularly for lower-rated and unrated securities. Liquidity can be
      reduced unpredictably in response to overall economic conditions or credit
      tightening. Municipal issuers may be adversely affected by rising health
      care costs, increasing unfunded pension liabilities, and by the phasing
      out of federal programs providing financial support. Unfavorable
      conditions and developments relating to projects financed with municipal
      securities can result in lower revenues to issuers of municipal
      securities, potentially resulting in defaults. Issuers often depend on
      revenues from these projects to make principal and interest payments. The
      value of municipal securities can also be adversely affected by changes in
      the financial condition of one or more individual municipal issuers or
      insurers of municipal issuers, regulatory

32 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



      and political developments, tax law changes or other legislative actions,
      and by uncertainties and public perceptions concerning these and other
      factors. Municipal securities may be more susceptible to down-grades or
      defaults during recessions or similar periods of economic stress. In
      recent periods, an increasing number of municipal issuers in the United
      States have defaulted on obligations and commenced insolvency proceedings.
      Financial difficulties of municipal issuers may continue or get worse. To
      the extent the Trust invests significantly in a single state, including
      Illinois, Massachusetts, Texas and Washington, or in securities the
      payments on which are dependent upon a single project or source of
      revenues, or that relate to a sector or industry, including health care
      facilities, education, transportation, special revenues and pollution
      control, the Trust will be more susceptible to associated risks and
      developments.

      With the increased use of technologies such as the Internet to conduct
      business, the Trust is susceptible to operational, information security
      and related risks. While the Trust's Adviser has established business
      continuity plans in the event of, and risk management systems to prevent,
      limit or mitigate, such cyber-attacks, there are inherent limitations in
      such plans and systems including the possibility that certain risks have
      not been identified. Furthermore, the Trust cannot control the
      cybersecurity plans and systems put in place by service providers to the
      Trust such as Brown Brothers Harriman & Co., the Trust's custodian and
      accounting agent, and American Stock Transfer & Trust Company ("AST"), the
      Trust's transfer agent. In addition, many beneficial owners of Trust
      shares hold them through accounts at broker-dealers, retirement platforms
      and other financial market participants over which neither the Trust nor
      Amundi Pioneer exercises control. Each of these may in turn rely on
      service providers to them, which are also subject to the risk of
      cyber-attacks. Cybersecurity failures or breaches at Amundi Pioneer or the
      Trust's service providers or intermediaries have the ability to cause
      disruptions and impact business operations, potentially resulting in
      financial losses, interference with the Trust's ability to calculate its
      net asset value, impediments to trading, the inability of Trust
      shareowners to effect share purchases or receive distributions, loss of or
      unauthorized access to private shareowners information and violations of
      applicable privacy and other laws, regulatory fines, penalties,
      reputational damage, or additional compliance costs. Such costs and losses
      may not be covered under any insurance. In addition, maintaining vigilance
      against cyber-attacks may involve substantial costs over time, and system
      enhancements may themselves be subject to cyber-attacks.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 33



2. Management Agreement

The Adviser manages the Trust's portfolio. Management fees payable under the
Trust's Advisory Agreement with the Adviser are calculated daily at the annual
rate of 0.60% of the Trust's average daily managed assets. "Managed assets"
means (a) the total assets of the Trust, including any form of investment
leverage, minus (b) all accrued liabilities incurred in the normal course of
operations, which shall not include any liabilities or obligations attributable
to investment leverage obtained through (i) indebtedness of any type
(including, without limitation, borrowing through a credit facility or the
issuance of debt securities), (ii) the issuance of preferred stock or other
similar preference securities, and/or (iii) any other means. For the six months
ended October 31, 2018, the net management fee was 0.60% (annualized) of the
Trust's average daily managed assets, which was equivalent to 0.86%
(annualized) of the Trust's average daily net assets.

In addition, under the management and administration agreements, certain other
services and costs, including accounting, regulatory reporting and insurance
premiums, are paid by the Trust as administrative reimbursements. Included in
"Due to affiliates" reflected on the Statement of Assets and Liabilities is
$35,542 in management fees, administrative costs and certain other
reimbursements payable to the Adviser at October 31, 2018.

3. Transfer Agent

AST serves as the transfer agent with respect to the Trust's common shares. The
Trust pays AST an annual fee, as is agreed to from time to time by the Trust
and AST, for providing such services.

In addition, the Trust reimbursed the transfer agent for out-of-pocket expenses
incurred by the transfer agent related to shareowner communications activities
such as proxy and statement mailings and outgoing calls.

Deutsche Bank Trust Company Americas ("Deutsche Bank") served as the transfer
agent, registrar, dividend-paying agent and auction agent with respect to the
Trust's auction preferred shares ("APS"). The Trust paid Deutsche Bank an
annual fee for providing such services.

4. Trust Shares

There are an unlimited number of common shares of beneficial interest
authorized.

34 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



Transactions in common shares of beneficial interest for the six months ended
October 31, 2018 and the year ended April 30, 2018 were as follows:



--------------------------------------------------------------------------------
                                                       10/31/18          4/30/18
--------------------------------------------------------------------------------
                                                                
Shares outstanding at beginning of period            22,771,349       22,771,349
Reinvestment of distributions                                --               --
--------------------------------------------------------------------------------
Shares outstanding at end of period                  22,771,349       22,771,349
================================================================================


The Trust may classify or reclassify any unissued shares of beneficial interest
into one or more series of preferred shares of beneficial interest.

As of October 31, 2018, the Trust has outstanding 1,250 Variable Rate MuniFund
Term Preferred Shares Series 2021 ("Series 2021 VMTP Shares or "VMTP Shares").
The Trust issued the VMTP Shares on February 9, 2018. See Note 5 for additional
information.

Prior to February 9, 2018, the Trust had outstanding 2,000 Series A APS and
2,040 Series B APS. The Trust mailed a notice of redemption and deposited funds
sufficient to redeem the APS with the auction agent on February 9, 2018. The
Trust redeemed all outstanding Series A APS and Series B APS on February 14,
2018 and February 15, 2018, respectively. See Note 6 for additional
information.

5. Variable Rate MuniFund Term Preferred Shares

The Trust has 1,250 shares issued and outstanding of Series 2021 VMTP Shares,
with a liquidation preference of $100,000 per share. VMTP Shares are issued via
private placement and are not publicly available.

The Trust is obligated to redeem its VMTP Shares by the date as specified in
its offering document ("Term Redemption Date"), unless earlier redeemed by the
Trust. VMTP Shares are subject to optional and mandatory redemption in certain
circumstances. The VMTP Shares may be redeemed at the option of the Trust,
subject to payment of premium for approximately one year following the date of
issuance ("Optional Redemption Date"), and at the redemption price per share
thereafter. The redemption price per share is equal to the sum of the
liquidation preference per share plus any accumulated but unpaid dividends. The
Trust may be obligated to redeem a certain amount of the VMTP Shares if it
fails to maintain certain asset coverage and leverage ratio requirements and
such failures are not cured by the applicable cure date. The Term Redemption
Date and Optional Redemption Date for the Trust's Series 2021 VMTP Shares are
August 2, 2021 and February 28, 2019, respectively.

VMTP Shares are subject to restrictions on transfer, generally do not trade,
and market quotations are generally not available. VMTP Shares are short-term
or short/intermediate-term instruments that pay a variable dividend rate tied
to a short-term index, plus an additional fixed "spread" amount

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 35



established at the time of issuance. For financial reporting purposes, the
liquidation preference of VMTP Shares is a liability and is recognized as a
component of "Variable Rate MuniFund Term Preferred Shares, net of deferred
offering costs" on the Statement of Assets and Liabilities.

Dividends on the VMTP Shares (which are treated as interest payments for
financial reporting purposes) are declared daily. The dividend rate for the
VMTP Shares is determined weekly. Unpaid dividends on VMTP Shares are
recognized as a component of "Dividend payable" on the Statement of Assets and
Liabilities. For the six months ended October 31, 2018, the Series 2021 VMTP
Shares paid an average dividend rate of 2.59%.

Costs incurred in connection with the Trust's offering of VMTP Shares were
recorded as a deferred charge, which is being amortized over the life of the
shares and is recognized as a component of "Variable Rate MuniFund Term
Preferred Shares, net of deferred offering costs" on the Statement of Assets
and Liabilities.

Transactions in the Series 2021 VMTP Shares during the Trust's current and
prior reporting periods were as follows:



--------------------------------------------------------------------------------------------------
                                Six Months Ended 10/31/18                    Year Ended 4/30/18
                                Shares             Amount                 Shares           Amount
--------------------------------------------------------------------------------------------------
                                                                         
VMTP Shares issued                  --               $ --                 1,250      $125,000,000
VMTP Shares exchanged               --                 --                    --                --
--------------------------------------------------------------------------------------------------
Net increase                        --               $ --                 1,250      $125,000,000
==================================================================================================


6. Redemption of APS

The Trust redeemed all of its outstanding APS at the liquidation preference per
share, together with accrued and unpaid dividends, if any, as of the redemption
date as follows:



--------------------------------------------------------------------------------
                                                                       Accrued
                                                                    and Unpaid
                    Shares          Redemption       Preference      Dividends
Series         Outstanding                Date        Per Share      Per Share
--------------------------------------------------------------------------------
                                                           
A                   2,000      February 14, 2018      $25,000          $12,288
--------------------------------------------------------------------------------
B                   2,040      February 15, 2018      $25,000          $12,975
--------------------------------------------------------------------------------


The Trust continues to employ leverage for investment purposes through the
issuance of VMTP Shares. See Note 5 for additional information.

7. Dividends to APS Shareowners

Prior to the redemption of the Trust's APS (See Note 6), dividends on Series A
and Series B were cumulative at a rate which reset every seven days based on
the results of an auction. Since February 2008, the Trust's auctions related to
the APS failed. Accordingly, during the period, dividends were paid at the

36 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



maximum rate on the auction dates described in the prospectus for the APS. The
maximum rate for each series was 125% of the 7 day commercial paper rate or
adjusted Kenny rate. Dividend rates on APS ranged from 1.414% to 3.260% during
the year ended April 30, 2018.

8. Subsequent Events

A monthly dividend was declared on November 5, 2018 from undistributed and
accumulated net investment income of $0.0525 per common share payable November
30, 2018, to common shareowners of record on November 16, 2018.

Subsequent to October 31, 2018, dividends declared and paid on VMTP Shares
totaled $285,381 through November 30, 2018.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 37



ADDITIONAL INFORMATION

During the period, there have been no material changes in the Trust's
investment objective or fundamental policies that have not been approved by the
shareowners. There have been no changes in the Trust's charter or By-Laws that
would delay or prevent a change in control of the Trust which has not been
approved by the shareowners. During the period, there have been no changes in
the principal risk factors associated with investment in the Trust. There were
no changes in the persons who are primarily responsible for the day-to-day
management of the Trust's portfolio. Notice is hereby given in accordance with
Section 23(c) of the Investment Company Act of 1940 that the Trust may
purchase, from time to time, its common shares in the open market.

Change in Independent Registered Public Accounting Firm

Prior to July 3, 2017 Pioneer Investment Management, Inc. ("the Adviser"), the
Trust's investment adviser, was an indirect, wholly owned subsidiary of
UniCredit S.p.A. ("UniCredit"). On that date, UniCredit completed the sale of
its Pioneer Investments business, which includes the Adviser, to Amundi (the
"Transaction"). As a result of the Transaction, the Adviser became an indirect,
wholly owned subsidiary of Amundi. Amundi is controlled by Credit Agricole S.A.
Amundi is headquartered in Paris, France, and, as of September 30, 2016, had
more than $1.1 trillion in assets under management worldwide.

Deloitte & Touche LLP ("D&T"), the Trust's previous independent registered
public accounting firm, informed the Audit Committee and the Board that it
would no longer be independent with respect to the Trust upon the completion of
the Transaction as a result of certain services being provided to Amundi and
Credit Agricole, and, accordingly, that it intended to resign as the Trust's
independent registered public accounting firm upon the completion of the
Transaction. D&T's resignation was effective on July 3, 2017, when the
Transaction was completed.

During the periods as to which D&T has served as the Trust's independent
registered public accounting firm, D&T's reports on the Trust's financial
statements have not contained an adverse opinion or disclaimer of opinion and
have not been qualified or modified as to uncertainty, audit scope or
accounting principles. Further, there have been no disagreements with D&T on
any matter of accounting principles or practices, financial statement
disclosure, or auditing scope or procedure, which, if not resolved to the
satisfaction of D&T, would have caused D&T to make reference to the subject
matter of the disagreement in connection with its report on the financial
statements. In addition, there have been no reportable events of the kind
described in Item 304(a)(1)(v) of Regulation S-K under the Securities Exchange
Act of 1934.

38 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



Effective immediately following the completion of the Transaction on July 3,
2017, the Board, acting upon the recommendation of the Audit Committee, engaged
an independent registered public accounting firm, Ernst & Young LLP ("EY").

Prior to its engagement, EY had advised the Trust's Audit Committee that EY had
identified the following matters, in each case relating to services rendered by
other member firms of Ernst & Young Global Limited, all of which are located
outside the United States, to UniCredit and certain of its subsidiaries during
the period commencing July 1, 2016, that it determined to be inconsistent with
the auditor independence rules set forth by the Securities and Exchange
Commission ("SEC"): (a) project management support services to UniCredit in the
Czech Republic, Germany, Italy, Serbia and Slovenia in relation to twenty-two
projects, that were determined to be inconsistent with Rule 2-01(c)(4)(vi) of
Regulation S-X (management functions); (b) two engagements for UniCredit in
Italy where fees were contingent/success based and that were determined to be
inconsistent with Rule 2-01(c)(5) of Regulation S-X (contingent fees); (c) four
engagements where legal and expert services were provided to UniCredit in the
Czech Republic and Germany, and twenty engagements where the legal advisory
services were provided to UniCredit in Austria, Czech Republic, Italy and
Poland, that were determined to be inconsistent with Rule 2-01(c)(4)(ix) and
(x) of Regulation S-X (legal and expert services); and (d) two engagements for
UniCredit in Italy involving assistance in the sale of certain assets, that
were determined to be inconsistent with Rule 2-01(c)(4)(viii) of Regulation S-X
(broker-dealer, investment adviser or investment banking services). None of the
foregoing services involved the Trust, any of the other funds in the Pioneer
Family of Funds or any other Pioneer entity sold by UniCredit in the
Transaction.

EY advised the Audit Committee that it had considered the matters described
above and had concluded that such matters would not impair EY's ability to
exercise objective and impartial judgment in connection with the audits of the
financial statements of the Trust under the SEC and Public Company Accounting
Oversight Board independence rules, and that a reasonable investor with
knowledge of all relevant facts and circumstances would reach the same
conclusion. Management and the Audit Committee considered these matters and
discussed the matters with EY and, based upon EY's description of the matters
and statements made by EY, Management and the Audit Committee believe that EY
will be capable of exercising objective and impartial judgment in connection
with the audits of the financial statements of the Trust, and Management
further believes that a reasonable investor with knowledge of all relevant
facts and circumstances would reach the same conclusion.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 39



Results of Shareholder Meeting

At the annual meeting held on September 20, 2018, shareowners of the Trust were
asked to consider the proposal described below. A report of the total votes
cast by the Trust's shareholders follows:

Proposal 1 - To elect three Class II Trustees



-----------------------------------------------------------
Nominee                         For               Withheld
-----------------------------------------------------------
                                            
Thomas J. Perna                 19,349,337        2,107,687
Marguerite A. Piret*                 1,250                0
Fred J. Ricciardi               19,966,136        1,490,888


*     Elected by preferred shares only

40 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



Approval of Investment Management Agreement

Amundi Pioneer Asset Management, Inc. ("APAM") serves as the investment adviser
to Pioneer Municipal High Income Trust (the "Trust") pursuant to an investment
management agreement between APAM and the Trust. In order for APAM to remain
the investment adviser of the Trust, the Trustees of the Trust must determine
annually whether to renew the investment management agreement for the Trust.

The contract review process began in January 2018 as the Trustees of the Trust
agreed on, among other things, an overall approach and timeline for the
process. Contract review materials were provided to the Trustees in March 2018,
July 2018 and September 2018. In addition, the Trustees reviewed and discussed
the Trust's performance at regularly scheduled meetings throughout the year,
and took into account other information related to the Trust provided to the
Trustees at regularly scheduled meetings, in connection with the review of the
Trust's investment management agreement.

In March 2018, the Trustees, among other things, discussed the memorandum
provided by Fund counsel that summarized the legal standards and other
considerations that are relevant to the Trustees in their deliberations
regarding the renewal of the investment management agreement, and reviewed and
discussed the qualifications of the investment management teams for the Trust,
as well as the level of investment by the Trust's portfolio managers in the
Trust. In July 2018, the Trustees, among other things, reviewed the Trust's
management fees and total expense ratios, the financial statements of APAM and
its parent companies, profitability analyses provided by APAM, and analyses
from APAM as to possible economies of scale. The Trustees also reviewed the
profitability of the institutional business of APAM and APAM's affiliate,
Amundi Pioneer Institutional Asset Management, Inc. ("APIAM" and, together with
APAM, "Amundi Pioneer"), as compared to that of APAM's fund management
business, and considered the differences between the fees and expenses of the
Trust and the fees and expenses of APAM's and APIAM's institutional accounts,
as well as the different services provided by APAM to the Trust and by APAM and
APIAM to the institutional accounts. The Trustees further considered contract
review materials, including additional materials received in response to the
Trustees' request, in September 2018.

At a meeting held on September 18, 2018, based on their evaluation of the
information provided by APAM and third parties, the Trustees of the Trust,
including the Independent Trustees voting separately, unanimously approved the
renewal of the investment management agreement for another year. In approving
the renewal of the investment management agreement, the Trustees considered
various factors that they determined were relevant, including the factors
described below. The Trustees did not identify any single factor as the
controlling factor in determining to approve the renewal of the agreement.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 41



Nature, Extent and Quality of Services

The Trustees considered the nature, extent and quality of the services that had
been provided by APAM to the Trust, taking into account the investment
objective and strategy of the Trust. The Trustees also reviewed APAM's
investment approach for the Trust and its research process. The Trustees
considered the resources of APAM and the personnel of APAM who provide
investment management services to the Trust. They also reviewed the amount of
non-Trust assets managed by the portfolio managers of the Trust. They
considered the non-investment resources and personnel of APAM that are involved
in APAM's services to the Trust, including APAM's compliance, risk management,
and legal resources and personnel. The Trustees noted the substantial attention
and high priority given by APAM's senior management to the Pioneer Fund
complex.

The Trustees considered that APAM supervises and monitors the performance of
the Trust's service providers and provides the Trust with personnel (including
Trust officers) and other resources that are necessary for the Trust's business
management and operations. The Trustees also considered that, as administrator,
APAM is responsible for the administration of the Trust's business and other
affairs. The Trustees considered the fees paid to APAM for the provision of
administration services.

Based on these considerations, the Trustees concluded that the nature, extent
and quality of services that had been provided by APAM to the Trust were
satisfactory and consistent with the terms of the investment management
agreement.

Performance of the Trust

In considering the Trust's performance, the Trustees regularly review and
discuss throughout the year data prepared by APAM and information comparing the
Trust's performance with the performance of its peer group of funds, as
classified by Morningstar, Inc. (Morningstar), and the performance of the
Trust's benchmark index. They also discuss the Trust's performance with APAM on
a regular basis. The Trustees' regular reviews and discussions were factored
into the Trustees' deliberations concerning the renewal of the investment
management agreement.

Management Fee and Expenses

The Trustees considered information showing the fees and expenses of the Trust
in comparison to the management fees and expense ratios of a peer group of
funds selected on the basis of criteria determined by the Independent Trustees
for this purpose using data provided by Strategic Insight Mutual Fund Research
and Consulting, LLC (Strategic Insight), an independent third party. The peer
group comparisons referred to below are organized in quintiles. Each quintile
represents one-fifth of the peer group. In all peer group comparisons referred
to below, first quintile is most favorable to the Trust's shareowners.

42 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



The Trustees considered that the Trust's management fee (based on managed
assets) for the most recent fiscal year was in the third quintile relative to
the management fees paid by other funds in its Strategic Insight peer group for
the comparable period. The Trustees considered that the expense ratio (based on
managed assets) of the Trust's common shares for the most recent fiscal year
was in the first quintile relative to its Strategic Insight peer group for the
comparable period.

The Trustees reviewed management fees charged by APAM and APIAM to
institutional and other clients, including publicly offered European funds
sponsored by APAM's affiliates, unaffiliated U.S. registered investment
companies (in a sub-advisory capacity), and unaffiliated foreign and domestic
separate accounts. The Trustees also considered APAM's costs in providing
services to the Trust and APAM's and APIAM's costs in providing services to the
other clients and considered the differences in management fees and profit
margins for fund and non-fund services. In evaluating the fees associated with
APAM's and APIAM's client accounts, the Trustees took into account the
respective demands, resources and complexity associated with the Trust and
other client accounts. The Trustees noted that, in some instances, the fee
rates for those clients were lower than the management fee for the Trust and
considered that, under the investment management agreement with the Trust, APAM
performs additional services for the Trust that it does not provide to those
other clients or services that are broader in scope, including oversight of the
Trust's other service providers and activities related to compliance and the
extensive regulatory and tax regimes to which the Trust is subject. The
Trustees also considered the entrepreneurial risks associated with APAM's
management of the Trust.

The Trustees concluded that the management fee payable by the Trust to APAM was
reasonable in relation to the nature and quality of the services provided by
APAM.

Profitability

The Trustees considered information provided by APAM regarding the
profitability of APAM with respect to the advisory services provided by APAM to
the Trust, including the methodology used by APAM in allocating certain of its
costs to the management of the Trust. The Trustees also considered APAM's
profit margin in connection with the overall operation of the Trust. They
further reviewed the financial results, including the profit margins, realized
by APAM and APIAM from non-fund businesses. The Trustees considered APAM's
profit margins in comparison to the limited industry data available and noted
that the profitability of any adviser was affected by numerous factors,
including its organizational structure and method for allocating expenses. The
Trustees concluded that APAM's profitability with respect to the management of
the Trust was not unreasonable.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 43



Economies of Scale

The Trustees considered the extent to which APAM may realize economies of scale
or other efficiencies in managing and supporting the Trust. Since the Trust is
a closed-end fund that has not raised additional capital, the Trustees
concluded that economies of scale were not a relevant consideration in the
renewal of the investment advisory agreement.

Other Benefits

The Trustees considered the other benefits that APAM enjoys from its
relationship with the Trust. The Trustees considered the character and amount
of fees paid or to be paid by the Trust, other than under the investment
management agreement, for services provided by APAM and its affiliates. The
Trustees further considered the revenues and profitability of APAM's businesses
other than the Fund business. To the extent applicable, the Trustees also
considered the benefits to the Trust and to APAM and its affiliates from the
use of "soft" commission dollars generated by the Trust to pay for research and
brokerage services.

The Trustees considered that Amundi Pioneer is the principal U.S. asset
management business of Amundi, which is one of the largest asset managers
globally. Amundi's worldwide asset management business manages over $1.7
trillion in assets (including the Pioneer Funds). The Trustees considered that
APAM's relationship with Amundi creates potential opportunities for APAM, APIAM
and Amundi that derive from APAM's relationships with the Trust, including
Amundi's ability to market the services of APAM globally. The Trustees noted
that APAM has access to additional research and portfolio management
capabilities as a result of its relationship with Amundi and Amundi's enhanced
global presence that may contribute to an increase in the resources available
to APAM. The Trustees considered that APAM and the Trust receive reciprocal
intangible benefits from the relationship, including mutual brand recognition
and, for the Trust, direct and indirect access to the resources of a large
global asset manager. The Trustees concluded that any such benefits received by
APAM as a result of its relationship with the Trust were reasonable.

Conclusion

After consideration of the factors described above as well as other factors,
the Trustees, including the Independent Trustees, concluded that the investment
management agreement for the Trust, including the fees payable thereunder, was
fair and reasonable and voted to approve the proposed renewal of the investment
management agreement.

44 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



Trustees, Officers and Service Providers

Trustees                                    Officers
Thomas J. Perna, Chairman                   Lisa M. Jones, President and
David R. Bock                                  Chief Executive Officer
Benjamin M. Friedman                        Mark E. Bradley, Treasurer and
Margaret B.W. Graham                           Chief Financial Officer
Lisa M. Jones                               Christopher J. Kelley, Secretary and
Lorraine H. Monchak                            Chief Legal Officer
Marguerite A. Piret
Fred J. Ricciardi
Kenneth J. Taubes

Investment Adviser and Administrator
Amundi Pioneer Asset Management, Inc.

Custodian and Sub-Administrator
Brown Brothers Harriman & Co.

Principal Underwriter
Amundi Pioneer Distributor, Inc.

Legal Counsel
Morgan, Lewis & Bockius LLP

Transfer Agent
American Stock Transfer & Trust Company

Proxy Voting Policies and Procedures of the Fund are available without charge,
upon request, by calling our toll free number (1-800-225-6292). Information
regarding how the Fund voted proxies relating to portfolio securities during
the most recent 12-month period ended June 30 is publicly available to
shareowners at www.amundipioneer.com. This information is also available on the
Securities and Exchange Commission's web site at www.sec.gov.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 45



                          This page is for your notes.

46 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



                          This page is for your notes.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 47



                          This page is for your notes.

48 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



                          This page is for your notes.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 49



                          This page is for your notes.

50 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



                          This page is for your notes.

           Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18 51



                          This page is for your notes.

52 Pioneer Municipal High Income Trust | Semiannual Report | 10/31/18



How to Contact Amundi Pioneer

We are pleased to offer a variety of convenient ways for you to contact us for
assistance or information.

You can call American Stock Transfer & Trust Company (AST) for:
--------------------------------------------------------------------------------
Account Information                                 1-800-710-0935

Or write to AST:
--------------------------------------------------------------------------------
For                                                 Write to

General inquiries, lost dividend checks,            American Stock
change of address, lost stock certificates,         Transfer & Trust
stock transfer                                      Operations Center
                                                    6201 15th Ave.
                                                    Brooklyn, NY 11219

Dividend reinvestment plan (DRIP)                   American Stock
                                                    Transfer & Trust
                                                    Wall Street Station
                                                    P.O. Box 922
                                                    New York, NY 10269-0560

Website www.amstock.com

For additional information, please contact your investment advisor or visit our
web site www.amundipioneer.com.

The Trust files a complete schedule of investments with the Securities and
Exchange Commission for the first and third quarters for each fiscal year on
Form N-Q. Shareowners may view the filed Form N-Q by visiting the Commission's
web site at www.sec.gov.



[LOGO]   Amundi Pioneer
         ==============
       ASSET MANAGEMENT

Amundi Pioneer Asset Management, Inc.
60 State Street
Boston, MA 02109

www.amundipioneer.com

Securities offered through Amundi Pioneer Distributor, Inc.
60 State Street, Boston, MA 02109
Underwriter of Pioneer Mutual Funds, Member SIPC
[C] 2018 Amundi Pioneer Asset Management 19442-12-1218




ITEM 2. CODE OF ETHICS.

(a) Disclose whether, as of the end of the period covered by the report, the
registrant has adopted a code of ethics that applies to the registrant's
principal executive officer, principal financial officer, principal accounting
officer or controller, or persons performing similar functions, regardless of
whether these individuals are employed by the registrant or a third party.  If
the registrant has not adopted such a code of ethics, explain why it has not
done so.

The registrant has adopted, as of the end of the period covered by this report,
a code of ethics that applies to the registrant's principal executive officer,
principal financial officer, principal accounting officer and controller.

(b) For purposes of this Item, the term "code of ethics" means written standards
that are reasonably designed to deter wrongdoing and to promote:

        (1) Honest and ethical conduct, including the ethical handling of actual
        or apparent conflicts of interest between personal and professional
        relationships;

        (2) Full, fair, accurate, timely, and understandable disclosure in
        reports and documents that a registrant files with, or submits to, the
        Commission and in other public communications made by the registrant;

        (3) Compliance with applicable governmental laws, rules, and
        regulations;

        (4) The prompt internal reporting of violations of the code to an
        appropriate person or persons identified in the code; and

        (5) Accountability for adherence to the code.

(c) The registrant must briefly describe the nature of any amendment, during the
period covered by the report, to a provision of its code of ethics that applies
to the registrant's principal executive officer, principal financial officer,
principal accounting officer or controller, or persons performing similar
functions, regardless of whether these individuals are employed by the
registrant or a third party, and that relates to any element of the code of
ethics definition enumerated in paragraph (b) of this Item. The registrant must
file a copy of any such amendment as an exhibit pursuant to Item 10(a), unless
the registrant has elected to satisfy paragraph (f) of this Item by posting its
code of ethics on its website pursuant to paragraph (f)(2) of this Item, or by
undertaking to provide its code of ethics to any person without charge, upon
request, pursuant to paragraph (f)(3) of this Item.

The registrant has made no amendments to the code of ethics during the period
covered by this report.

(d) If the registrant has, during the period covered by the report, granted a
waiver, including an implicit waiver, from a provision of the code of ethics to
the registrant's principal executive officer, principal financial officer,
principal accounting officer or controller, or persons performing similar
functions, regardless of whether these individuals are employed by the
registrant or a third party, that relates to one or more of the items set forth
in paragraph (b) of this Item, the registrant must briefly describe the nature
of the waiver, the name of the person to whom the waiver was granted, and the
date of the waiver.

Not applicable.

(e) If the registrant intends to satisfy the disclosure requirement under
paragraph (c) or (d) of this Item regarding an amendment to, or a waiver from,
a provision of its code of ethics that applies to the registrant's principal
executive officer, principal financial officer, principal accounting officer or
controller, or persons performing similar functions and that relates to any
element of the code of ethics definition enumerated in paragraph (b) of this
Item by posting such information on its Internet website, disclose the
registrant's Internet address and such intention.

Not applicable.

(f) The registrant must:

        (1) File with the Commission, pursuant to Item 12(a)(1), a copy of
        its code of ethics that applies to the registrant's principal
        executive officer,principal financial officer, principal accounting
        officer or controller, or persons performing similar functions,
        as an exhibit to its annual
        report on this Form N-CSR (see attachment);

        (2) Post the text of such code of ethics on its Internet website and
        disclose, in its most recent report on this Form N-CSR, its Internet
        address and the fact that it has posted such code of ethics on its
        Internet website; or

        (3) Undertake in its most recent report on this Form N-CSR to provide to
        any person without charge, upon request, a copy of such code of ethics
        and explain the manner in which such request may be made.
	See Item 10(2)

ITEM 3. AUDIT COMMITTEE FINANCIAL EXPERT.

(a) (1)  Disclose that the registrant's board of trustees has determined that
         the registrant either:

    (i)  Has at least one audit committee financial expert serving on its audit
         committee; or

    (ii) Does not have an audit committee financial expert serving on its audit
         committee.

The registrant's Board of Trustees has determined that the registrant has at
least one audit committee financial expert.

    (2) If the registrant provides the disclosure required by paragraph
(a)(1)(i) of this Item, it must disclose the name of the audit committee
financial expert and whether that person is "independent." In order to be
considered "independent" for purposes of this Item, a member of an audit
committee may not, other than in his or her capacity as a member of the audit
committee, the board of trustees, or any other board committee:

    (i)  Accept directly or indirectly any consulting, advisory, or other
         compensatory fee from the issuer; or

    (ii) Be an "interested person" of the investment company as defined in
         Section 2(a)(19) of the Act (15 U.S.C. 80a-2(a)(19)).

Ms. Marguerite A. Piret, an independent trustee, is such an audit committee
financial expert.

    (3) If the registrant provides the disclosure required by paragraph (a)(1)
(ii) of this Item, it must explain why it does not have an audit committee
financial expert.

Not applicable.


ITEM 4. PRINCIPAL ACCOUNTANT FEES AND SERVICES.

(a) Disclose, under the caption AUDIT FEES, the aggregate fees billed for each
of the last two fiscal years for professional services rendered by the principal
accountant for the audit of the registrant's annual financial statements or
services that are normally provided by the accountant in connection with
statutory and regulatory filings or engagements for those fiscal years.

N/A

(b) Disclose, under the caption AUDIT-RELATED FEES, the aggregate fees billed in
each of the last two fiscal years for assurance and related services by the
principal accountant that are reasonably related to the performance of the audit
of the registrant's financial statements and are not reported under
paragraph (a) of this Item. Registrants shall describe the nature of the
services comprising the fees disclosed under this category.

N/A


(c) Disclose, under the caption TAX FEES, the aggregate fees billed in each of
the last two fiscal years for professional services rendered by the principal
accountant for tax compliance, tax advice, and tax planning. Registrants shall
describe the nature of the services comprising the fees disclosed under this
category.

N/A

(d) Disclose, under the caption ALL OTHER FEES, the aggregate fees billed in
each of the last two fiscal years for products and services provided by the
principal accountant, other than the services reported in paragraphs (a) through
(c) of this Item. Registrants shall describe the nature of the services
comprising the fees disclosed under this category.

N/A

(e) (1) Disclose the audit committee's pre-approval policies and procedures
described in paragraph (c)(7) of Rule 2-01 of Regulation S-X.

 PIONEER FUNDS
            APPROVAL OF AUDIT, AUDIT-RELATED, TAX AND OTHER SERVICES
                       PROVIDED BY THE INDEPENDENT AUDITOR

                  SECTION I - POLICY PURPOSE AND APPLICABILITY

The Pioneer Funds recognize the importance of maintaining the independence of
their outside auditors. Maintaining independence is a shared responsibility
involving Amudi Pioneer Asset Management, Inc, the audit committee and
the independent auditors.

The Funds recognize that a Fund's independent auditors: 1) possess knowledge of
the Funds, 2) are able to incorporate certain services into the scope of the
audit, thereby avoiding redundant work, cost and disruption of Fund personnel
and processes, and 3) have expertise that has value to the Funds. As a result,
there are situations where it is desirable to use the Fund's independent
auditors for services in addition to the annual audit and where the potential
for conflicts of interests are minimal. Consequently, this policy, which is
intended to comply with Rule 210.2-01(C)(7), sets forth guidelines and
procedures to be followed by the Funds when retaining the independent audit firm
to perform audit, audit-related tax and other services under those
circumstances, while also maintaining independence.

Approval of a service in accordance with this policy for a Fund shall also
constitute approval for any other Fund whose pre-approval is required pursuant
to Rule 210.2-01(c)(7)(ii).

In addition to the procedures set forth in this policy, any non-audit services
that may be provided consistently with Rule 210.2-01 may be approved by the
Audit Committee itself and any pre-approval that may be waived in accordance
with Rule 210.2-01(c)(7)(i)(C) is hereby waived.

Selection of a Fund's independent auditors and their compensation shall be
determined by the Audit Committee and shall not be subject to this policy.



                               SECTION II - POLICY

---------------- -------------------------------- -------------------------------------------------
SERVICE           SERVICE CATEGORY DESCRIPTION      SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES
CATEGORY
---------------- -------------------------------- -------------------------------------------------
                                            
I.  AUDIT        Services that are directly       o Accounting research assistance
SERVICES         related to performing the        o SEC consultation, registration
                 independent audit of the Funds     statements, and reporting
                                                  o Tax accrual related matters
                                                  o Implementation of new accounting
                                                    standards
                                                  o Compliance letters (e.g. rating agency
                                                    letters)
                                                  o Regulatory reviews and assistance
                                                    regarding financial matters
                                                  o Semi-annual reviews (if requested)
                                                  o Comfort letters for closed end
                                                    offerings
---------------- -------------------------------- -------------------------------------------------
II.              Services which are not           o AICPA attest and agreed-upon procedures
AUDIT-RELATED    prohibited under Rule            o Technology control assessments
SERVICES         210.2-01(C)(4) (the "Rule")      o Financial reporting control assessments
                 and are related extensions of    o Enterprise security architecture
                 the audit services support the     assessment
                 audit, or use the
                 knowledge/expertise gained
                 from the audit procedures as a
                 foundation to complete the
                 project.  In most cases, if
                 the Audit-Related Services are
                 not performed by the Audit
                 firm, the scope of the Audit
                 Services would likely
                 increase.  The Services are
                 typically well-defined and
                 governed by accounting
                 professional standards (AICPA,
                 SEC, etc.)
---------------- -------------------------------- -------------------------------------------------

 ------------------------------------- ------------------------------------
                                    
   AUDIT COMMITTEE APPROVAL POLICY               AUDIT COMMITTEE
                                                REPORTING POLICY
 ------------------------------------- ------------------------------------
                                    
 o "One-time" pre-approval             o A summary of all such
   for the audit period for all          services and related fees
   pre-approved specific service         reported at each regularly
   subcategories.  Approval of the       scheduled Audit Committee
   independent auditors as               meeting.
   auditors for a Fund shall
   constitute pre approval for
   these services.
 ------------------------------------- ------------------------------------
 o "One-time" pre-approval             o A summary of all such
   for the fund fiscal year within       services and related fees
   a specified dollar limit              (including comparison to
   for all pre-approved                  specified dollar limits)
   specific service subcategories        reported quarterly.

 o Specific approval is
   needed to exceed the
   pre-approved dollar limit for
   these services (see general
   Audit Committee approval policy
   below for details on obtaining
   specific approvals)

 o Specific approval is
   needed to use the Fund's
   auditors for Audit-Related
   Services not denoted as
   "pre-approved", or
   to add a specific service
   subcategory as "pre-approved"
 ------------------------------------- ------------------------------------




                     SECTION III - POLICY DETAIL, CONTINUED

----------------------- --------------------------- -----------------------------------------------
   SERVICE CATEGORY          SERVICE CATEGORY        SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES
                               DESCRIPTION
----------------------- --------------------------- -----------------------------------------------
                                              
III. TAX SERVICES       Services which are not      o Tax planning and support
                        prohibited by the Rule,     o Tax controversy assistance
                        if an officer of the Fund   o Tax compliance, tax returns, excise
                        determines that using the     tax returns and support
                        Fund's auditor to provide   o Tax opinions
                        these services creates
                        significant synergy in
                        the form of efficiency,
                        minimized disruption, or
                        the ability to maintain a
                        desired level of
                        confidentiality.
----------------------- --------------------------- -----------------------------------------------

------------------------------------- -------------------------
  AUDIT COMMITTEE APPROVAL POLICY         AUDIT COMMITTEE
                                          REPORTING POLICY
------------------------------------- -------------------------
------------------------------------- -------------------------
o "One-time" pre-approval             o A summary of
  for the fund fiscal  year             all such services and
  within a specified dollar limit       related fees
  				        (including comparison
  			                to specified dollar
  			                limits) reported
  			                quarterly.

o Specific approval is
  needed to exceed the
  pre-approved dollar limits for
  these services (see general
  Audit Committee approval policy
  below for details on obtaining
  specific approvals)

o Specific approval is
  needed to use the Fund's
  auditors for tax services not
  denoted as pre-approved, or to add a specific
  service subcategory as
  "pre-approved"
------------------------------------- -------------------------




                     SECTION III - POLICY DETAIL, CONTINUED

----------------------- --------------------------- -----------------------------------------------
   SERVICE CATEGORY          SERVICE CATEGORY        SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES
                               DESCRIPTION
----------------------- --------------------------- -----------------------------------------------
                                              
IV.  OTHER SERVICES     Services which are not      o Business Risk Management support
                        prohibited by the Rule,     o Other control and regulatory
A. SYNERGISTIC,         if an officer of the Fund     compliance projects
UNIQUE QUALIFICATIONS   determines that using the
                        Fund's auditor to provide
                        these services creates
                        significant synergy in
                        the form of efficiency,
                        minimized disruption,
                        the ability to maintain a
                        desired level of
                        confidentiality, or where
                        the Fund's auditors
                        posses unique or superior
                        qualifications to provide
                        these services, resulting
                        in superior value and
                        results for the Fund.
----------------------- --------------------------- -----------------------------------------------

--------------------------------------- ------------------------
    AUDIT COMMITTEE APPROVAL POLICY         AUDIT COMMITTEE
                                            REPORTING POLICY
------------------------------------- --------------------------
                                   
o "One-time" pre-approval             o A summary of
  for the fund fiscal year within       all such services and
  a specified dollar limit              related fees
  			               (including comparison
  			                to specified dollar
  				        limits) reported
                                        quarterly.
o Specific approval is
  needed to exceed the
  pre-approved dollar limits for
  these services (see general
  Audit Committee approval policy
  below for details on obtaining
  specific approvals)

o Specific approval is
  needed to use the Fund's
  auditors for "Synergistic" or
  "Unique Qualifications" Other
  Services not denoted as
  pre-approved to the left, or to
  add a specific service
  subcategory as "pre-approved"
------------------------------------- --------------------------




                     SECTION III - POLICY DETAIL, CONTINUED

----------------------- ------------------------- -----------------------------------------------
   SERVICE CATEGORY         SERVICE CATEGORY        SPECIFIC PROHIBITED SERVICE SUBCATEGORIES
                              DESCRIPTION
----------------------- ------------------------- -----------------------------------------------
                                            
PROHIBITED  SERVICES    Services which result     1. Bookkeeping or other services
                        in the auditors losing       related to the accounting records or
                        independence status          financial statements of the audit
                        under the Rule.              client*
                                                  2. Financial information systems design
                                                     and implementation*
                                                  3. Appraisal or valuation services,
                                                     fairness* opinions, or
                                                     contribution-in-kind reports
                                                  4. Actuarial services (i.e., setting
                                                     actuarial reserves versus actuarial
                                                     audit work)*
                                                  5. Internal audit outsourcing services*
                                                  6. Management functions or human
                                                     resources
                                                  7. Broker or dealer, investment
                                                     advisor, or investment banking services
                                                  8. Legal services and expert services
                                                     unrelated to the audit
                                                  9. Any other service that the Public
                                                     Company Accounting Oversight Board
                                                     determines, by regulation, is
                                                     impermissible
----------------------- ------------------------- -----------------------------------------------

------------------------------------------- ------------------------------
     AUDIT COMMITTEE APPROVAL POLICY               AUDIT COMMITTEE
                                                  REPORTING POLICY
------------------------------------------- ------------------------------
o These services are not to be              o A summary of all
  performed with the exception of the(*)      services and related
  services that may be permitted              fees reported at each
  if they would not be subject to audit       regularly scheduled
  procedures at the audit client (as          Audit Committee meeting
  defined in rule 2-01(f)(4)) level           will serve as continual
  the firm providing the service.             confirmation that has
  				              not provided any
                                              restricted services.
------------------------------------------- ------------------------------

--------------------------------------------------------------------------------
GENERAL AUDIT COMMITTEE APPROVAL POLICY:
o For all projects, the officers of the Funds and the Fund's auditors will each
  make an assessment to determine that any proposed projects will not impair
  independence.

o Potential services will be classified into the four non-restricted service
  categories and the "Approval of Audit, Audit-Related, Tax and Other
  Services" Policy above will be applied. Any services outside the specific
  pre-approved service subcategories set forth above must be specifically
  approved by the Audit Committee.

o At least quarterly, the Audit Committee shall review a report summarizing the
  services by service category, including fees, provided by the Audit firm as
  set forth in the above policy.

--------------------------------------------------------------------------------


    (2) Disclose the percentage of services described in each of paragraphs (b)
   through (d) of this Item that were approved by the audit committee pursuant
   to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X.

N/A


(f) If greater than 50 percent, disclose the percentage of hours expended on the
principal accountants engagement to audit the registrant's financial statements
for the most recent fiscal year that were attributed to work performed by
persons other than the principal accountant's full-time, permanent employees.

N/A

(g) Disclose the aggregate non-audit fees billed by the registrants accountant
for services rendered to the registrant, and rendered to the registrants
investment adviser (not including any sub-adviser whose role is primarily
portfolio management and is subcontracted with or overseen by another investment
adviser), and any entity controlling, controlled by, or under common control
with the adviser that provides ongoing services to the registrant for each of
the last two fiscal years of the registrant.

N/A

(h) Disclose whether the registrants audit committee of the board of trustees
has considered whether the provision of non-audit services that were rendered to
the registrants investment adviser (not including any subadviser whose role is
primarily portfolio management and is subcontracted with or overseen by another
investment adviser), and any entity controlling, controlled by, or under common
control with the investment adviser that provides ongoing services to the
registrant that were not pre-approved pursuant to paragraph (c)(7)(ii) of
Rule 2-01 of Regulation S-X is compatible with maintaining the principal
accountant's independence.

The Fund's audit committee of the Board of Trustees
has considered whether the provision of non-audit
services that were rendered to the Affiliates (as
defined) that were not pre- approved pursuant to
paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X is
compatible with maintaining the principal accountant's
independence.

ITEM 5. AUDIT COMMITTEE OF LISTED REGISTRANTS

(a) If the registrant is a listed issuer as defined in Rule 10A-3
under the Exchange Act (17 CFR 240.10A-3), state whether
or not the registrant has a separately-designated standing
 audit committee established in accordance with Section
3(a)(58)(A) of the Exchange Act (15 U.S.C. 78c(a)(58)(A)).
If the registrant has such a committee, however designated,
identify each committee member. If the entire board of directors
is acting as the registrant's audit committee as specified in
Section 3(a)(58)(B) of the Exchange Act (15 U.S.C. 78c(a)(58)(B)),
so state.

N/A

(b) If applicable, provide the disclosure required by Rule 10A-3(d)
under the Exchange Act (17 CFR 240.10A-3(d)) regarding an exemption
from the listing standards for audit committees.

N/A

ITEM 6. SCHEDULE OF INVESTMENTS.

File Schedule of Investments in securities of unaffiliated issuers
as of the close of the reporting period as set forth in 210.1212
of Regulation S-X [17 CFR 210.12-12], unless the schedule is
included as part of the report to shareholders filed under Item
1 of this Form.

Included in Item 1


ITEM 7. DISCLOSURE OF PROXY VOTING POLICIES AND PROCEDURES FOR
CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

A closed-end management investment company that is filing an annual report on
this Form N-CSR must, unless it invests exclusively in non-voting securities,
describe the policies and procedures that it uses to determine how to vote
proxies relating to portfolio securities, including the procedures that the
company uses when a vote presents a conflict between the interests of its
shareholders, on the one hand, and those of the company's investment adviser;
principal underwriter; or any affiliated person (as defined in Section 2(a)(3)
of the Investment Company Act of 1940 (15 U.S.C. 80a-2(a)(3)) and the rules
thereunder) of the company, its investment adviser, or its principal
underwriter, on the other. Include any policies and procedures of the company's
investment adviser, or any other third party, that the company uses, or that are
used on the company's behalf, to determine how to vote proxies relating to
portfolio securities.

N/A



ITEM 8. PORTFOLIO MANAGERS OF CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

(a) If the registrant is a closed-end management investment company that
is filing an annual report on this Form N-CSR,provide the following
information:
(1) State the name, title, and length of service of the person or persons
employed by or associated with the registrant or an investment adviser
of the registrant who are primarily responsible for the day-to-day management
of the registrant's portfolio ("Portfolio Manager"). Also state each Portfolio
Manager's business experience during the past 5 years.


N/A


ITEM 9. PURCHASES OF EQUITY SECURITIES BY CLOSED-END MANAGEMENT
INVESTMENT COMPANY AND AFFILIATED PURCHASERS.

(a) If the registrant is a closed-end management investment company,
in the following tabular format, provide the information specified in
paragraph (b) of this Item with respect to any purchase made by or on
behalf of the registrant or any affiliated purchaser, as defined in
Rule 10b-18(a)(3) under the Exchange Act (17 CFR 240.10b-18(a)(3)), of
shares or other units of any class of the registrant's equity securities
that is registered by the registrant pursuant to Section 12 of the
Exchange Act (15 U.S.C. 781).

N/A


ITEM 10. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS.

Describe any material changes to the procedures by which shareholders
may recommend nominees to the registrant's board of directors, where
those changes were implemented after the registrant last provided
disclosure in response to the requirements of Item 407(c)(2)(iv) of
Regulation S-R(17 CFR 229.407)(as required by Item 22(b)(15))
of Schedule 14A (17 CFR 240.14a-101), or this Item.


There have been no material changes to the procedures by which the
shareholders may recommend nominees to the registrant's board of
directors since the registrant last provided disclosure in response
to the requirements of Item 407(c)(2)(iv) of Regulation S-R of Schedule 14(A)
in its definitive proxy statement, or this item.


ITEM 11. CONTROLS AND PROCEDURES.

(a) Disclose the conclusions of the registrant's principal executive and
principal financials officers, or persons performing similar functions,
regarding the effectiveness of the registrant's disclosure
controls and procedures (as defined in Rule 30a-3(c) under the Act (17 CFR
270.30a-3(c))) as of a date within 90 days of the filing date of the report
that includes the disclosure required by this paragraph,
based on the evaluation of these controls and procedures required by Rule
30a-3(b) under the Act (17 CFR 270.30(a)-3(b) and Rules 13a-15(b) or 15d-15(b)
under the Exchange Act (17 CFR 240.13a-15(b) or 240.15d-15(b)).

The registrant's principal executive officer
and principal financial officer have
concluded that the registrant's disclosure
controls and procedures are effective based
on the evaluation of these controls and
procedures as of a date within 90 days of the
filing date of this report.


(b) Disclose any change in the registrant's internal control over financial
reporting (as defined in Rule 30a-3(d) under the Act (17CFR 270.30a-3(d)) that
occured during the second fiscal quarter of the period covered by this report
that has materially affected, or is reasonably likely to materially affect,
the registrant's internal control over financial reporting.

There were no significant changes in the
registrant's internal control over financial
reporting that occurred during the second
fiscal quarter of the period covered by this
report that have materially affected, or are
reasonably likely to materially affect, the
registrant's internal control over financial
reporting.

The registrant's principal executive officer and principal financial
officer, however, voluntarily are reporting the following information:

In August of 2006 the registrant's investment adviser
enhanced its internal procedures for reporting performance
information required to be included in prospectuses.
Those enhancements involved additional internal controls
over the appropriateness of performance data
generated for this purpose.  Such enhancements were made
following an internal review which identified
prospectuses relating to certain classes of shares of
a limited number of registrants where, inadvertently,
performance information not reflecting the deduction of
applicable sales charges was included. Those prospectuses
were revised, and the revised prospectuses were distributed to
shareholders.

Item 12. Disclosure of Securities Lending Activities for Closed-End
Management Investment Companies.

(a) If the registrant is a closed-end management investment company,
provide the following dollar amounts of income and compensation related
to the securities lending activities of the registrant during its most
recent fiscal year:

N/A

(1) Gross income from securities lending activities;

N/A

(2) All fees and/or compensation for each of the following securities
lending activities and related services: any share of revenue generated
by the securities lending program paid to the securities lending agent(s)
(revenue split); fees paid for cash collateral management services
(including fees deducted from a pooled cash collateral reinvestment
vehicle) that are not included in the revenue split; administrative
fees that are not included in the revenue split; fees for
indemnification that are not included in the revenue split; rebates
paid to borrowers; and any other fees relating to the securities lending
program that are not included in the revenue split, including a description
of those other fees;

N/A

(3) The aggregate fees/compensation disclosed pursuant to paragraph (2); and

N/A

(4) Net income from securities lending activities (i.e., the dollar amount in
paragraph (1) minus the dollar amount in paragraph (3)).

If a fee for a service is included in the revenue split, state that the fee
is included in the revenue split.

N/A

(b) If the registrant is a closed-end management investment company, describe
the services provided to the registrant by the securities lending agent in
the registrants most recent fiscal year.

N/A


ITEM 13. EXHIBITS.

(a) File the exhibits listed below as part of this Form. Letter or number the
exhibits in the sequence indicated.

(1) Any code of ethics, or amendment thereto, that is the subject of the
disclosure required by Item 2, to the extent that the registrant intends to
satisfy the Item 2 requirements through filing of an exhibit.



(2) A separate certification for each principal executive officer and principal
financial officer of the registrant as required by Rule 30a-2(a) under the Act
(17 CFR 270.30a-2(a)) , exactly as set forth below:

Filed herewith.





                                   SIGNATURES

                          [See General Instruction F]


Pursuant to the requirements of the Securities Exchange Act of 1934 and the
Investment Company Act of 1940, the registrant has duly caused this report to be
signed on its behalf by the undersigned, thereunto duly authorized.


(Registrant) Pioneer Municipal High Income Trust


By (Signature and Title)* /s/ Lisa M. Jones
Lisa M. Jones, President & Chief Executive Officer

Date December 28, 2018


Pursuant to the requirements of the Securities Exchange Act of 1934 and the
Investment Company Act of 1940, this report has been signed below by the
following persons on behalf of the registrant and in the capacities and on the
dates indicated.


By (Signature and Title)* /s/ Lisa M. Jones
Lisa M. Jones, President & Chief Executive Officer

Date December 28, 2018


By (Signature and Title)* /s/ Mark E. Bradley
Mark E. Bradley, Treasurer & Chief Accounting & Financial Officer

Date December 28, 2018

* Print the name and title of each signing officer under his or her signature.