<?xml version="1.0"?>

<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>5</documentType>

    <periodOfReport>2003-03-31</periodOfReport>


    <notSubjectToSection16>1</notSubjectToSection16>

    <form3HoldingsReported>0</form3HoldingsReported>

    <form4TransactionsReported>0</form4TransactionsReported>

    <issuer>
        <issuerCik>0000848077</issuerCik>
        <issuerName>PUTNAM HIGH YIELD MUNICIPAL TRUST</issuerName>
        <issuerTradingSymbol>PYM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001200517</rptOwnerCik>
            <rptOwnerName>MUFSON MICHAEL J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>PUTNAM LLC</rptOwnerStreet1>
            <rptOwnerStreet2>ONE POST OFFICE SQUARE L5</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Managing Director</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>



    <ownerSignature>
        <signatureName>Michael J. Mufson</signatureName>
        <signatureDate>2003-08-20</signatureDate>
    </ownerSignature>

</ownershipDocument>

