<SEC-DOCUMENT>0001235802-21-000114.txt : 20210825
<SEC-HEADER>0001235802-21-000114.hdr.sgml : 20210825
<ACCEPTANCE-DATETIME>20210825162651
ACCESSION NUMBER:		0001235802-21-000114
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210823
FILED AS OF DATE:		20210825
DATE AS OF CHANGE:		20210825

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Hinnendael James J
		CENTRAL INDEX KEY:			0001348356

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-15010
		FILM NUMBER:		211207164

	MAIL ADDRESS:	
		STREET 1:		129 MARTEN STREET
		CITY:			MONDOVI
		STATE:			WI
		ZIP:			54755

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MARTEN TRANSPORT LTD
		CENTRAL INDEX KEY:			0000799167
		STANDARD INDUSTRIAL CLASSIFICATION:	TRUCKING (NO LOCAL) [4213]
		IRS NUMBER:				391140809
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		129 MARTEN ST
		CITY:			MONDOVI
		STATE:			WI
		ZIP:			54755
		BUSINESS PHONE:		7159264216

	MAIL ADDRESS:	
		STREET 1:		3400 PLAZA VII
		STREET 2:		45 SOUTH SEVENTH ST
		CITY:			MINNEAPOLIS
		STATE:			MN
		ZIP:			55402
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-08-23</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000799167</issuerCik>
        <issuerName>MARTEN TRANSPORT LTD</issuerName>
        <issuerTradingSymbol>MRTN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001348356</rptOwnerCik>
            <rptOwnerName>Hinnendael James J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>129 MARTEN STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MONDOVI</rptOwnerCity>
            <rptOwnerState>WI</rptOwnerState>
            <rptOwnerZipCode>54755</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Exec. VP and CFO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-08-23</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>7255</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>15.84</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>153420.7</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">These shares were withheld to cover the estimated tax withholding obligations in connection with the issuance of 16,302 shares released from the Issuer's deferred compensation plan which terminated effective May 5, 2021.</footnote>
        <footnote id="F2">Includes: (i) 6,040 shares granted under a Performance Unit Award Agreement that vest on 12/31/2021 through 12/31/2025; (ii) 2,020 shares granted under a Performance Unit Award Agreement that vest on 12/31/2021 through 12/31/2024; (iii) 3,060 shares granted under a Performance Unit Award Agreement that vest on 12/31/2021 through 12/31/2023; (iv) 2,130 shares granted under a Performance Unit Award Agreement that vest on 12/31/2021 through 12/31/2022; (v) 2,375 shares granted under a Performance Unit Award Agreement that vest on 12/31/2021; and (vi) 32,602.70 shares that the reporting person has deferred under the Issuer's deferred compensation plan.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ James J. Hinnendael</signatureName>
        <signatureDate>2021-08-25</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
