<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-09-13</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001099160</issuerCik>
        <issuerName>BEASLEY BROADCAST GROUP INC</issuerName>
        <issuerTradingSymbol>BBGI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000310051</rptOwnerCik>
            <rptOwnerName>KING LUTHER CAPITAL MANAGEMENT CORP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>301 COMMERCE SUITE 1600</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>FORT WORTH</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>76102</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001406372</rptOwnerCik>
            <rptOwnerName>LKCM Private Discipline Master Fund, SPC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>PO BOX 309GT</rptOwnerStreet1>
            <rptOwnerStreet2>UGLAND HOUSE, SOUTH CHURCH STREET</rptOwnerStreet2>
            <rptOwnerCity>GRAND CAYMAN</rptOwnerCity>
            <rptOwnerState>E9</rptOwnerState>
            <rptOwnerZipCode>00000</rptOwnerZipCode>
            <rptOwnerStateDescription>CAYMAN ISLANDS</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001406371</rptOwnerCik>
            <rptOwnerName>LKCM Investment Partnership, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>301 COMMERCE STREET</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1600</rptOwnerStreet2>
            <rptOwnerCity>FORT WORTH</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>76102</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001406297</rptOwnerCik>
            <rptOwnerName>King John Bryan</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>301 COMMERCE STREET</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1600</rptOwnerStreet2>
            <rptOwnerCity>FORT WORTH</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>76102</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001290407</rptOwnerCik>
            <rptOwnerName>King Luther Jr</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>301 COMMERCE STREET</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1600</rptOwnerStreet2>
            <rptOwnerCity>FORT WORTH</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>76102</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-09-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>7086</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>3.6446</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>944734</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Includes shares beneficially owned by LKCM Private Discipline Master Fund, SPC (PDP) and LKCM Investment Partnership, L.P. (LIP).  LKCM Private Discipline Management, L.P. (PD Management) is the manager of PDP, and LKCM Alternative Management, LLC (PD Alternative) is the general partner of PD Management.  LKCM Investment Partnership GP, LLC (LIP GP) is the general partner of LIP.  Luther King Capital Management Corporation is the investment manager for PDP and LIP.  J. Luther King, Jr. is a controlling shareholder of LKCM and a controlling member of LIP GP.  J. Luther King, Jr. and J. Bryan King are controlling members of PD Alternative.  Each of the reporting persons expressly disclaims beneficial ownership of the securities reported herein, except to the extent of its pecuniary interest herein.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>J. Bryan King, for Luther King Capital Management Corporation</signatureName>
        <signatureDate>2010-09-15</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>J. Bryan King, for LKCM Private Discipline Master Fund, SPC</signatureName>
        <signatureDate>2010-09-15</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>J. Luther King, Jr., for LKCM Investment Partnership, L.P.</signatureName>
        <signatureDate>2010-09-15</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>J. Bryan King</signatureName>
        <signatureDate>2010-09-15</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>J. Luther King, Jr.</signatureName>
        <signatureDate>2010-09-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
