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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2020-03-18</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001144980</issuerCik>
        <issuerName>ASBURY AUTOMOTIVE GROUP INC</issuerName>
        <issuerTradingSymbol>ABG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001358706</rptOwnerCik>
            <rptOwnerName>ABRAMS CAPITAL MANAGEMENT, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 BERKELEY STREET, 21ST FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001165407</rptOwnerCik>
            <rptOwnerName>ABRAMS CAPITAL MANAGEMENT, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 BERKELEY STREET, 21ST FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001112443</rptOwnerCik>
            <rptOwnerName>ABRAMS CAPITAL, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 BERKELEY STREET, 21ST FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001292250</rptOwnerCik>
            <rptOwnerName>Abrams David C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 BERKELEY STREET, 21ST FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001292420</rptOwnerCik>
            <rptOwnerName>Abrams Capital Partners II, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 BERKELEY STREET, 21ST FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-03-18</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>113270</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>43.2732</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2109610</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-03-19</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>8606</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>43.2331</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2118216</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F6"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents the weighted average purchase price of shares purchased in a series of open market transactions on the transaction date at prices ranging from $42.96156 to $43.32947 per share. The Reporting Persons undertake to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares purchased at each price.</footnote>
        <footnote id="F2">Represents the weighted average purchase price of shares purchased in a series of open market transactions on the transaction date at prices ranging from $43.136 to $43.33786 per share. The Reporting Persons undertake to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares purchased at each price.</footnote>
        <footnote id="F3">Shares reported herein as beneficially owned by Abrams Capital, LLC (&quot;Abrams Capital&quot;) represent shares held for the account of Abrams Capital Partners II, L.P. (&quot;ACP II&quot;) and other private investment funds for which Abrams Capital serves as general partner. Shares reported herein for Abrams Capital Management, L.P. (the &quot;LP&quot;) and Abrams Capital Management, LLC (the &quot;LLC&quot;) represent the above-referenced shares beneficially owned by ACP II and shares beneficially owned by other private investment funds for which the LP serves as investment manager. The LLC is the general partner of the LP. Shares reported herein for Mr. Abrams represent the above referenced shares reported for Abrams Capital and the LLC. Mr. Abrams is the managing member of Abrams Capital and the LLC.</footnote>
        <footnote id="F4">Each of the Reporting Persons disclaims beneficial ownership of the shares reported herein except to the extent of its or his pecuniary interest in such shares, and the inclusion of such securities in this report shall not be deemed an admission of beneficial ownership for purposes of Section 16 or for any other purpose.</footnote>
        <footnote id="F5">Of the shares purchased on March 18, 2020, 91,719 shares were held for the account of ACP II and all of such shares may be deemed to have been beneficially owned by Abrams Capital, Mr. Abrams, the LP and the LLC.</footnote>
        <footnote id="F6">Of the shares purchased on March 19, 2020, 6,968 shares were held for the account of ACP II and all of such shares may be deemed to have been beneficially owned by Abrams Capital, Mr. Abrams, the LP and the LLC. As of March 20, 2019, 1,716,441 of the shares reported herein are held for the account of ACP II, Abrams Capital may be deemed to beneficially own 2,034,820 of the shares reported herein, and Mr. Abrams, the LP and the LLC may be deemed to beneficially own all of such shares.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Abrams Capital Management, L.P., by Abrams Capital Management, LLC, the General Partner, by David C. Abrams, Managing Member</signatureName>
        <signatureDate>2020-03-20</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Abrams Capital Partners II, L.P., by Abrams Capital LLC, the General Partner, by David C. Abrams, Managing Member</signatureName>
        <signatureDate>2020-03-20</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Abrams Capital Management, LLC, by David C. Abrams, Managing Member</signatureName>
        <signatureDate>2020-03-20</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Abrams Capital, LLC, by David C. Abrams, Managing Member</signatureName>
        <signatureDate>2020-03-20</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ David C. Abrams</signatureName>
        <signatureDate>2020-03-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
