-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 WqviJO+J+el/Bpx00gB41yk3GZFDIZBCUmHpP16cOi7JW+P6YhiXBSY5nwxEWnbZ
 aF1rHRBzmEH0UWXGeNlcQQ==

<SEC-DOCUMENT>0001140361-10-005031.txt : 20100209
<SEC-HEADER>0001140361-10-005031.hdr.sgml : 20100209
<ACCEPTANCE-DATETIME>20100209165837
ACCESSION NUMBER:		0001140361-10-005031
CONFORMED SUBMISSION TYPE:	5
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20091231
FILED AS OF DATE:		20100209
DATE AS OF CHANGE:		20100209

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MANNING PATRICK T
		CENTRAL INDEX KEY:			0001205460

	FILING VALUES:
		FORM TYPE:		5
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-31993
		FILM NUMBER:		10585016

	MAIL ADDRESS:	
		STREET 1:		20810 FERNBUSH LANE
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77073

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			STERLING CONSTRUCTION CO INC
		CENTRAL INDEX KEY:			0000874238
		STANDARD INDUSTRIAL CLASSIFICATION:	HEAVY CONSTRUCTION OTHER THAN BUILDING CONST - CONTRACTORS [1600]
		IRS NUMBER:				251655321
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		2751 CENTERVILLE RD.
		STREET 2:		SUITE 3131
		CITY:			WILMINGTON
		STATE:			DE
		ZIP:			19803
		BUSINESS PHONE:		3024789170

	MAIL ADDRESS:	
		STREET 1:		20810 FERNBUSH LANE
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77073

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	OAKHURST CO INC
		DATE OF NAME CHANGE:	19950831

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	OAKHURST CAPITAL INC
		DATE OF NAME CHANGE:	19931130
</SEC-HEADER>
<DOCUMENT>
<TYPE>5
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 5
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>5</documentType>

    <periodOfReport>2009-12-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <form3HoldingsReported>0</form3HoldingsReported>

    <form4TransactionsReported>0</form4TransactionsReported>

    <issuer>
        <issuerCik>0000874238</issuerCik>
        <issuerName>STERLING CONSTRUCTION CO INC</issuerName>
        <issuerTradingSymbol>STRL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001205460</rptOwnerCik>
            <rptOwnerName>MANNING PATRICK T</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>20810 FERNBUSH LANE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77073</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Executive Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-09-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value>L</value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>500</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>16.36</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>56527</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-09-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value>L</value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>100</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>16.35</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>56427</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">These shares were sold as a result of a margin call by the reporting person's broker.</footnote>
        <footnote id="F2">This number reflects a correction in the number of shares owned by the reporting person after the date of the reported sale.  Because the reporting person has not been able to trace the source of the error, this number is based on the number of shares held by the reporting person according to the records of the reporting person's brokerage firm.</footnote>
        <footnote id="F3">After taking into account the sale of 10,000 shares on September 25, 2009, which was timely reported on Form 4, the reporting person held 46,427 shares at December 31, 2009</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Roger M. Barzun under a Power of Attorney</signatureName>
        <signatureDate>2010-02-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----