Exhibit 10.1

SECOND AMENDMENT

This Second Amendment (this “Amendment”) to the Credit Agreement referred to
below is dated as of May 12, 2011, by and among MANTECH INTERNATIONAL
CORPORATION, a Delaware corporation, in its capacity as Borrower under the
Credit Agreement referred to below (the “Borrower”), the Lenders party hereto
(the “Consenting Lenders”) pursuant to an authorization (in the form attached
hereto as Exhibit A, each a “Lender Authorization”), and BANK OF AMERICA, N.A.,
as administrative agent (the “Administrative Agent”) for the Lenders party to
the Credit Agreement referred to below.

STATEMENT OF PURPOSE:

The Borrower, the Lenders, certain other financial institutions and the
Administrative Agent are parties to the Credit Agreement dated as of April 30,
2007 (as amended by that certain First Amendment and Consent dated as of
December 18, 2009 and as may be further amended, restated, supplemented or
otherwise modified from time to time, the “Credit Agreement”).

The Borrower has requested that the Administrative Agent and the Lenders agree
to amend the Credit Agreement as more specifically set forth herein. Subject to
the terms and conditions set forth herein, the Administrative Agent and each of
the Consenting Lenders have agreed to grant such request of the Borrower.

NOW, THEREFORE, for good and valuable consideration, the receipt and sufficiency
of which are hereby acknowledged, the parties hereto hereby agree as follows:

1. Capitalized Terms. All capitalized terms not otherwise defined herein
(including, without limitation, in the introductory paragraph and the statement
of purpose hereto) shall have the meanings assigned thereto in the Credit
Agreement (as amended by this Amendment).

2. Credit Agreement Amendment. Section 7.06(e) of the Credit Agreement is hereby
amended and restated in its entirety to read as follows:

“(e) the Borrower may (i) make Restricted Payments to any Person that owns an
Equity Interest in the Borrower, ratably according to such Person’s holdings of
the type of Equity Interest in respect of which such Restricted Payment is being
made (unless otherwise agreed by all of the owners of a particular class of
Equity Interests and provided that any such agreement by any class does not have
an adverse effect with respect to any other class of Equity Interests) or
(ii) repurchase its Equity Interests pursuant to a stock repurchase plan
approved by the Borrower’s board of directors, all such repurchases of Equity
Interests pursuant to clause (ii) together with all such Restricted Payments
made pursuant to clause (i) in an aggregate amount not to exceed $80,000,000 in
any fiscal year, so long as each of the following conditions is satisfied:

(i) no Event of Default shall have occurred and be continuing;

(ii) the Borrower demonstrates (to the satisfaction of the Administrative Agent)
compliance with the financial covenants set forth in Section 7.12 both before
and after giving pro forma effect to the following transactions;

(iii) immediately after giving effect to such purchase or acquisition, (A) the
Consolidated Leverage Ratio of the Borrower and its Subsidiaries shall not be
greater than 2.75 to 1.00 and (B) the Consolidated Fixed Charge Coverage Ratio

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of the Borrower and its Subsidiaries shall not be less than 1.20 to 1.00, in
each case, such compliance to be determined on the basis of the financial
information most recently delivered to the Administrative Agent and the Lenders
pursuant to Section 6.01(a) or (b) as though such purchase or other acquisition
had been consummated as of the first day of the fiscal period covered thereby;
and

(iv) immediately after giving effect to such purchase or acquisition (including,
without limitation, the funding of any Loans in connection therewith), the
Aggregate Commitments shall exceed the Total Outstandings by at least
$50,000,000; and”

3. Conditions to Effectiveness. Upon the satisfaction of each of the following
conditions, this Amendment shall be deemed to be effective as of the date
hereof:

(a) the Administrative Agent shall have received counterparts of this Amendment
executed by the Administrative Agent (on behalf of itself and each of the
Consenting Lenders by virtue of each Consenting Lender’s execution of a Lender
Authorization) and the Borrower;

(b) the Administrative Agent shall have received executed Lender Authorizations
from the Consenting Lenders constituting Required Lenders; and

(c) the Administrative Agent shall have received such other instruments,
documents and certificates as the Administrative Agent shall reasonably request
in connection with the execution of this Amendment.

4. Effect of the Amendment. Except as expressly provided herein, the Credit
Agreement and the other Loan Documents shall remain unmodified and in full force
and effect. Except as expressly set forth herein, this Amendment shall not be
deemed (a) to be a waiver of, or consent to, a modification or amendment of, any
other term or condition of the Credit Agreement or any other Loan Document,
(b) to prejudice any other right or rights which the Administrative Agent or the
Lenders may now have or may have in the future under or in connection with the
Credit Agreement or the other Loan Documents or any of the instruments or
agreements referred to therein, as the same may be amended, restated,
supplemented or otherwise modified from time to time, (c) to be a commitment or
any other undertaking or expression of any willingness to engage in any further
discussion with the Borrower or any other Person with respect to any waiver,
amendment, modification or any other change to the Credit Agreement or the Loan
Documents or any rights or remedies arising in favor of the Lenders or the
Administrative Agent, or any of them, under or with respect to any such
documents or (d) to be a waiver of, or consent to or a modification or amendment
of, any other term or condition of any other agreement by and among the
Borrower, on the one hand, and the Administrative Agent or any other Lender, on
the other hand. References in the Credit Agreement to “this Agreement” (and
indirect references such as “hereunder”, “hereby”, “herein”, and “hereof”) and
in any Loan Document to the Credit Agreement shall be deemed to be references to
the Credit Agreement as modified hereby.

5. Representations and Warranties/No Default. By their execution hereof,

(a) the Borrower hereby certifies, represents and warrants to the Administrative
Agent and the Lenders that after giving effect to the amendment set forth in
Section 2 above, each of the representations and warranties set forth in the
Credit Agreement and the other Loan Documents is true and correct in all
material respects (unless such representation and warranty is subject to a
materiality qualifier in which case it must be true and correct in all respects)
as of the date hereof (except to the extent such representations and warranties
expressly refer to an earlier

 

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date, in which case they shall be true and correct in all material respects
(unless such representation and warranty is subject to a materiality qualifier
in which case it must be true and correct in all respects) as of the earlier
date) and that no Default or Event of Default has occurred or is continuing
under the Credit Agreement; and

(b) the Borrower hereby certifies, represents and warrants to the Administrative
Agent and the Lenders that:

(i) it has the right, power and authority and has taken all necessary corporate
and other action to authorize the execution, delivery and performance of this
Amendment and each of the other documents executed in connection herewith to
which it is a party in accordance with their respective terms and the
transactions contemplated hereby; and

(ii) this Amendment and each other document executed in connection herewith has
been duly executed and delivered by the duly authorized officers of the
Borrower, and each such document constitutes the legal, valid and binding
obligation of the Borrower, enforceable in accordance with its terms, except as
may be limited by bankruptcy, insolvency, reorganization, moratorium or similar
state or federal debtor relief laws from time to time in effect which affect the
enforcement of creditors’ rights in general and the availability of equitable
remedies.

6. Reaffirmations. The Borrower (a) agrees that the transactions contemplated by
this Amendment shall not limit or diminish the obligations of the Borrower
under, or release the Borrower from any obligations under the Guaranty
Agreement, the Collateral Agreement and each other Security Document to which it
is a party, (b) confirms and reaffirms its obligations under the Guaranty
Agreement, the Collateral Agreement and each other Security Document to which it
is a party and (c) agrees that the Guaranty Agreement, the Collateral Agreement
and each other Security Document to which it is a party remain in full force and
effect and are hereby ratified and confirmed. In furtherance of the
reaffirmations set forth in this Section 6 the Borrower hereby grants to the
Administrative Agent, for the ratable benefit of the Secured Parties, a security
interest in, all Collateral and all proceeds thereof as security for the
Obligations, in each case subject to any applicable terms and conditions set
forth in the Guaranty Agreement, the Collateral Agreement and each other
Security Document to which it is a party.

7. Governing Law. THIS AMENDMENT SHALL BE GOVERNED BY, AND CONSTRUED IN
ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK, WITHOUT REFERENCE TO THE
CONFLICTS OF LAW PRINCIPLES THEREOF.

8. Counterparts. This Amendment may be executed by one or more of the parties
hereto in any number of separate counterparts and all of said counterparts taken
together shall be deemed to constitute one and the same instrument.

9. Electronic Transmission. A facsimile, telecopy, pdf or other reproduction of
this Amendment may be executed by one or more parties hereto, and an executed
copy of this Amendment may be delivered by one or more parties hereto by
facsimile or similar instantaneous electronic transmission device pursuant to
which the signature of or on behalf of such party can be seen, and such
execution and delivery shall be considered valid, binding and effective for all
purposes. At the request of any party hereto, all parties hereto agree to
execute an original of this Amendment as well as any facsimile, telecopy, pdf or
other reproduction hereof.

[Signature Pages Follow]

 

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IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be duly
executed as of the date and year first above written.

 

BORROWER: MANTECH INTERNATIONAL CORPORATION By:  

/s/ Kevin M. Phillips

  Name:   Kevin M. Phillips   Title:   Executive Vice President and     Chief
Financial Officer

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BANK OF AMERICA, N.A., as Administrative Agent (on behalf of itself and the
Consenting Lenders who have executed a Lender Authorization) and as L/C Issuer
and a Lender By:  

/s/ Jim Langley

  Name:   Jim Langley   Title:   Vice President