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<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

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    <periodOfReport>2019-06-17</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000912752</issuerCik>
        <issuerName>SINCLAIR BROADCAST GROUP INC</issuerName>
        <issuerTradingSymbol>SBGI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001248331</rptOwnerCik>
            <rptOwnerName>LEADER MARTIN R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>4133 LOSILLIAS DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SARASOTA</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>34238</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

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            </transactionCoding>
            <transactionTimeliness>
                <value>E</value>
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            <transactionAmounts>
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                <transactionPricePerShare>
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        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>Clinton R. Black, V, Esq., on behalf of Martin Leader, by Power of Attorney</signatureName>
        <signatureDate>2019-06-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
