<SEC-DOCUMENT>0001044797-12-000009.txt : 20120214
<SEC-HEADER>0001044797-12-000009.hdr.sgml : 20120214
<ACCEPTANCE-DATETIME>20120214151940
ACCESSION NUMBER:		0001044797-12-000009
CONFORMED SUBMISSION TYPE:	SC 13G
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20120214
DATE AS OF CHANGE:		20120214

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MANTECH INTERNATIONAL CORP
		CENTRAL INDEX KEY:			0000892537
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-MANAGEMENT SERVICES [8741]
		IRS NUMBER:				221852179
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-78749
		FILM NUMBER:		12608571

	BUSINESS ADDRESS:	
		STREET 1:		12015 LEE JACKSON MEMORIAL HIGHWAY
		CITY:			FAIRFAX
		STATE:			VA
		ZIP:			22033-3300
		BUSINESS PHONE:		703-218-6000

	MAIL ADDRESS:	
		STREET 1:		12015 LEE JACKSON MEMORIAL HIGHWAY
		CITY:			FAIRFAX
		STATE:			VA
		ZIP:			22033-3300

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			NEW SOUTH CAPITAL MANAGEMENT INC
		CENTRAL INDEX KEY:			0001044797
		IRS NUMBER:				621237220
		STATE OF INCORPORATION:			TN
		FISCAL YEAR END:			0331

	FILING VALUES:
		FORM TYPE:		SC 13G

	BUSINESS ADDRESS:	
		STREET 1:		999 S. SHADY GROVE ROAD
		STREET 2:		SUITE 501
		CITY:			MEMPHIS
		STATE:			TN
		ZIP:			38120
		BUSINESS PHONE:		9017615561

	MAIL ADDRESS:	
		STREET 1:		999 S. SHADY GROVE ROAD
		STREET 2:		SUITE 501
		CITY:			MEMPHIS
		STATE:			TN
		ZIP:			38120
</SEC-HEADER>
<DOCUMENT>
<TYPE>SC 13G
<SEQUENCE>1
<FILENAME>mant.txt
<DESCRIPTION>SC 13G MANT
<TEXT>
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C.  20549

SCHEDULE 13G

(Amendment No. )*


ManTech International Corporation
(Name of Issuer)


Common Stock
(Title of Class of Securities)


564563104
(Cusip Number)


December 31, 2011
(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to
which this Schedule is filed:

[x] Rule 13d-1(b)
[ ] Rule 13d-1(c)
[ ] Rule 13d-1(d)

*The remainder of this cover page shall be filled out for a
reporting person's initial filing on this form with respect
to the subject class of securities, and for any subsequent
amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover
page shall not be deemed to be "filed" for the purpose of
Section 18 of the Securities Exchange Act of 1934 ("Act")
or otherwise subject to the liabilities of that section of
the Act but shall be subject to all other provisions of the
Act (however, see the Notes).


1.  NAME OF REPORTING PERSON
S.S. OR I.R.S. INDENTIFICATION NO. OF ABOVE PERSON:

NewSouth Capital Management, Inc.
Tax ID #: 62-1237220

2.	 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*(a)[ ]
                                                        (b)[ ]

3.	 SEC USE ONLY

4.	 CITIZENSHIP OR PLACE OF ORGANIZATION
    	 Tennessee


NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING
PERSON WITH:

5.	SOLE VOTING POWER
	1,217,426

6.	SHARED VOTING POWER
	None


7.	SOLE DISPOSITIVE POWER
	1,504,801

8.	SHARED DISPOSITIVE POWER
        None


9.	AGGREGATE AMOUNT BENEFICALLY OWNED BY EACH REPORTING
        PERSON
      1,504,801

10.	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES
        CERTAIN SHARES
        N/A


11.	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
        6.4%

12.	TYPE OF REPORTING PERSON*
        I/A


Item 1. (a)  Name of Issuer:

         ManTech International Corporation

Item 1. (b)  Address of Issuer's Principal Executive
             Offices:

		 12015 Lee Jackson Highway
		 Faifax, VA 22033


Item 2. (a)  Name of Person Filing:

             NewSouth Capital Management, Inc.


Item 2. (b)  Address of Principal Business Office:

             999 S. Shady Grove Rd. Suite 501
             Memphis, TN  38120


Item 2. (c) Citizenship:

            USA


Item 2. (d) Title of Class of Securities:

		Common Stock


Item 2. (e) CUSIP Number:

		564563104


Item 3. (e) /x/ Investment Adviser registered under Section
		203 of the Investment Advisers Act of 1940

Item 4.  Ownership:

(a)	Amount Beneficially Owned:
        1,504,801
(b)	Percent of Class:
        6.4%
(c)	Number of Shares as to which such person has:
(i)	Sole Power to vote or to direct the
        vote:	1,217,426
(ii)	Shared Power to vote or to direct the
        vote:	None
(iii)	Sole Power to dispose or to direct the
        disposition of:	1,504,801
(iv)	Shared Power to dispose or to direct
        the disposition of:	None

Of the 1,504,801 shares being reported, 3,155 or .01% of
the outstanding shares of Common Stock of
ManTech International Corporation are managed by
NewSouth Capital Management, Inc. through a
Morgan Keegan Preferred Program ("MKPfd")
whereby accounts are placed with NewSouth for
management.  Although discretionary responsibility for the
accounts is with NewSouth, MKPfd retains responsibility for
SEC filings should their cumulative holdings trigger the
need for 13G reporting.
Of the 1,504,801 shares being reported, 9,459 or .04% of
the outstanding shares of Common Stock of
ManTech International Corporation are managed by
NewSouth Capital Management, Inc. through
a Thomas Weisel Partners Investment
Management Consulting Program whereby accounts are placed
with NewSouth for management.  Although discretionary
responsibility for the accounts is with NewSouth, Thomas
Weisel Partners retains responsibility for SEC filings
should their cumulative holdings trigger the need for 13G
reporting.

Item 5. Ownership of Five Percent or Less of a Class:  N/A

Item 6.  Ownership of More than Five Percent on Behalf of
         Another Person:

NewSouth Capital Management is an Investment Advisor and in
such capacity acquired the securities on behalf of it's
Advisor clients.  No single client's interest relates to
more than 5% of the class.

Item 7.  Identification and Classification of the
Subsidiary Which Acquired the Security Being Reported on By
the Parent Holding Company:  N/A

Item 8.  Identification and Classification of Members of
the Group:  N/A

Item 9.  Notice of Dissolution of Group:  N/A


Item 10.  Certification:

By signing below I certify that, to the best of my
knowledge and belief, the securities referred to above were
acquired in the ordinary course of business and were not
acquired for the purpose of and do not have the effect of
changing or influencing the control of the issuer of such
securities and were not acquired in connection with or as a
participant in any transaction having such purposes or
effect.

After reasonable inquiry and to the best of my knowledge
and belief, I certify that the information set forth in
this statement is true, complete and correct.

Date:	02/14/2012 as of 12/31/2011


Signature:__________________________

Name: 	David M. Newman
Title:	Vice President
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>