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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0001140361-05-006490.txt : 20050817
<SEC-HEADER>0001140361-05-006490.hdr.sgml : 20050817
<ACCEPTANCE-DATETIME>20050817181918
ACCESSION NUMBER:		0001140361-05-006490
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050815
FILED AS OF DATE:		20050817
DATE AS OF CHANGE:		20050817

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			KNIGHT TRANSPORTATION INC
		CENTRAL INDEX KEY:			0000929452
		STANDARD INDUSTRIAL CLASSIFICATION:	TRUCKING (NO LOCAL) [4213]
		IRS NUMBER:				860649974
		STATE OF INCORPORATION:			AZ
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		5601 W BUCKEYE RD
		CITY:			PHOENIX
		STATE:			AZ
		ZIP:			85043
		BUSINESS PHONE:		6022692000

	MAIL ADDRESS:	
		STREET 1:		5601 W BUCKEYE RD
		CITY:			PHOENIX
		STATE:			AZ
		ZIP:			85043

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SCUDDER MARK A
		CENTRAL INDEX KEY:			0001181048

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32396
		FILM NUMBER:		051034338

	MAIL ADDRESS:	
		STREET 1:		411 S. 13TH STREET
		STREET 2:		SUITE 200
		CITY:			LINCOLN
		STATE:			NE
		ZIP:			68508
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-08-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000929452</issuerCik>
        <issuerName>KNIGHT TRANSPORTATION INC</issuerName>
        <issuerTradingSymbol>KNX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001181048</rptOwnerCik>
            <rptOwnerName>SCUDDER MARK A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5601 WEST BUCKEYE ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PHOENIX</rptOwnerCity>
            <rptOwnerState>AZ</rptOwnerState>
            <rptOwnerZipCode>85043</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, par value $0.01 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2005-08-15</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>364</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>23.55</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4702</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Each independent director of Knight Transportation, Inc. (&quot;Knight&quot;) may elect to receive shares of Knight common stock in lieu of cash for director's fees.  If an independent director elects to receive Knight stock as his director compensation, Knight issues stock to the independent directors on February 15 and August 15 of each year as payment of accrued director's fees for the preceding six month periods ending December 31 and June 30, respectively, at the closing market price for such shares as of the trading day prior to issuance.  The shares reflected in this Form 4 were shares received by Mr. Scudder in lieu of cash for director's fees.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Mark A. Scudder</signatureName>
        <signatureDate>2005-08-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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