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

    <schemaVersion>X0205</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2012-05-07</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000109758</issuerCik>
        <issuerName>ARBITRON INC</issuerName>
        <issuerTradingSymbol>ARB</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001358706</rptOwnerCik>
            <rptOwnerName>ABRAMS CAPITAL MANAGEMENT, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 BERKELEY STREET, 22ND 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, 22ND 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</rptOwnerStreet1>
            <rptOwnerStreet2>22ND FLOOR</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</rptOwnerStreet1>
            <rptOwnerStreet2>22ND FLOOR</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>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2715943</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">These securities are held by investment funds, the general partner and/or investment adviser of which is directly or indirectly controlled by David C. Abrams. In such capacity, Mr. Abrams may be deemed to beneficially own the reported securities.</footnote>
        <footnote id="F2">These securities are held by investment funds for which Abrams Capital Management, L.P. (the &quot;LP&quot;) serves as investment adviser. Abrams Capital Management, LLC (the &quot;LLC&quot;) serves as the general partner of the LP. In their respective capacities, each of the LP and the LLC may be deemed to beneficially own the reported securities.</footnote>
        <footnote id="F3">A portion of these securities are held by investment funds for which Abrams Capital, LLC (&quot;Abrams Capital&quot;) serves as general partner. In such capacity, Abrams Capital may be deemed to beneficially own the reported securities.</footnote>
        <footnote id="F4">Each Reporting Person disclaims beneficial ownership of the reported securities except to the extent of its pecuniary interest therein, 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">As of May 2, 2012, Abrams Capital may be deemed to beneficially own 2,542,807 shares of Common Stock and Mr. Abrams, the LP and the LLC may be deemed to beneficially own 2,715,943 shares of Common Stock.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Abrams Capital Management, L.P., by Abrams Capital Management, LLC, the General Partner, by David C. Abrams, Managing Member</signatureName>
        <signatureDate>2012-05-17</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Abrams Capital Management, LLC, by David C. Abrams, Managing Member</signatureName>
        <signatureDate>2012-05-17</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Abrams Capital, LLC, by David C. Abrams, Managing Member</signatureName>
        <signatureDate>2012-05-17</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ David C. Abrams</signatureName>
        <signatureDate>2012-05-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
