<SUBMISSION>
<ACCESSION-NUMBER>0001140361-13-046131
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20131211
<FILING-DATE>20131213
<DATE-OF-FILING-DATE-CHANGE>20131213
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>CELADON GROUP INC
<CIK>0000865941
<ASSIGNED-SIC>4213
<IRS-NUMBER>133361050
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>0630
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>ONE CELADON DRIVE
<STREET2>9503 E 33RD STREET
<CITY>INDIANAPOLIS
<STATE>IN
<ZIP>46235-4207
<PHONE>(317) 972-7000
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>ONE CELADON DRIVE
<STREET2>9503 E 33RD STREET
<CITY>INDIANAPOLIS
<STATE>IN
<ZIP>46235-4207
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>LANGHAM CATHERINE A
<CIK>0001191351
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-34533
<FILM-NUMBER>131276602
</FILING-VALUES>
<MAIL-ADDRESS>
<STREET1>LANGHAM LOGISTICS, INC.
<STREET2>5335 WEST 74TH STREET
<CITY>INDIANAPOLIS
<STATE>IN
<ZIP>46268
</MAIL-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2013-12-11</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000865941</issuerCik>
        <issuerName>CELADON GROUP INC</issuerName>
        <issuerTradingSymbol>CGI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001191351</rptOwnerCik>
            <rptOwnerName>LANGHAM CATHERINE A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5902 TRADING POST PLACE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CARMEL</rptOwnerCity>
            <rptOwnerState>IN</rptOwnerState>
            <rptOwnerZipCode>46033-8823</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2013-12-11</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3688</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>38583</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents a restricted stock award under the Celadon Group, Inc. 2006 Omnibus Incentive Plan, as amended. The award is subject to certain vesting, holding, and forfeiture provisions.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Catherine A. Langham, by Heidi Hornung-Scherr, attorney-in-fact, pursuant to a POA previously filed with the SEC</signatureName>
        <signatureDate>2013-12-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
