<SEC-DOCUMENT>0001235802-18-000091.txt : 20180702
<SEC-HEADER>0001235802-18-000091.hdr.sgml : 20180702
<ACCEPTANCE-DATETIME>20180702170259
ACCESSION NUMBER:		0001235802-18-000091
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20180629
FILED AS OF DATE:		20180702
DATE AS OF CHANGE:		20180702

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			TURNER JOHN H
		CENTRAL INDEX KEY:			0001253983

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-15010
		FILM NUMBER:		18933574

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>2018-06-29</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001253983</rptOwnerCik>
            <rptOwnerName>TURNER JOHN H</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>Senior Vice President of Sales</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2018-06-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>24.87</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>52506.71</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Represents dividend equivalent rights that accrued on June 29, 2018.</footnote>
        <footnote id="F2">Includes: (i) 2,950 shares granted under a Performance Unit Award Agreement that vest on 12/31/2018 through 12/31/2022; (ii) 5,933 shares granted under a Performance Unit Award Agreement that vest on 12/31/2018 through 12/31/2021; (iii) 1,150 shares granted under a Performance Unit Award Agreement that vest on 12/31/2018 through 12/31/2020; (iv) 783 shares granted under a Performance Unit Award Agreement that vest on 12/31/2018 through 12/31/2019; (v) 391 shares granted under a Performance Unit Award Agreement that vest on 12/31/2018 and (vi)23,350.71 shares that the reporting person has deferred under the Issuer's deferred compensation plan.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ James J. Hinnendael, attorney-in-fact</signatureName>
        <signatureDate>2018-07-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
