Exhibit 3.1

SECOND AMENDED AND RESTATED

CERTIFICATE OF INCORPORATION

ENGILITY HOLDINGS, INC.

FIRST: The name of the corporation (hereinafter referred to as the “Corporation”) is Engility Holdings, Inc.

SECOND: The address of the registered office of the Corporation in the State of Delaware is Corporation Trust Center, 1209 Orange Street, Wilmington, New Castle County, Delaware 19801. The name of its registered agent at such address is The Corporation Trust Company.

THIRD: The purposes of the Corporation are to engage in, promote, conduct and carry on any lawful acts or activities for which corporations may be organized under the General Corporation Law of the State of Delaware (the “DGCL”).

FOURTH: The total number of shares of stock which the Corporation shall have authority to issue is One Hundred (100) shares of Common Stock having a par value of $0.01 per share (the “Common Stock”).

FIFTH: The Corporation is to have perpetual existence.

SIXTH: The private property or assets of the stockholders of the Corporation shall not to any extent whatsoever be subject to the payment of the debts of the Corporation.

SEVENTH: Elections of directors need not be by written ballot unless otherwise provided in the Bylaws of the Corporation (as amended from time to time, the “Bylaws”).

EIGHTH: The business of the Corporation shall be managed by the board of directors of the Corporation (the “Board of Directors”). The number of directors which shall constitute the whole Board of Directors shall be fixed by, or in the manner provided in the Bylaws. None of the directors need be a stockholder or a resident of the State of Delaware.

NINTH: A director of the Corporation shall not be personally liable to the Corporation or its stockholders for monetary damages for breach of fiduciary duty as a director, except for liability (i) for any breach of the director’s duty of loyalty to the Corporation or its stockholders, (ii) for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law, (iii) under Section 174 of the DGCL, or (iv) for any transaction from which the director derived an improper personal benefit. If the DGCL is amended to authorize corporate action further eliminating or limiting the personal liability of directors, then the liability of a director of the Corporation shall be eliminated or limited to the fullest extent permitted by the DGCL, as so amended.

Any repeal or modification of the foregoing paragraph shall not adversely affect any right or protection of a director of the Corporation existing at the time of such repeal or modification.

TENTH: Unless the Corporation consents in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware shall be the sole and exclusive forum for (i) any derivative action or proceeding brought on behalf of the Corporation, (ii) any action asserting a claim of breach of a fiduciary duty owed by any director, officer or other employee of the Corporation to the Corporation or the Corporation’s stockholders, (iii) any action asserting a claim arising pursuant to any provision of the DGCL or the Corporation’s Certificate of Incorporation or the Bylaws, or (iv) any action asserting a claim governed by the internal affairs doctrine except as to each of (i) through (iv) above, for any claim as to which the Court of Chancery determines that there is an indispensable party not subject to the jurisdiction of the Court of Chancery (and the indispensable party does not consent to the personal jurisdiction of the Court of Chancery within ten days following such determination), which is vested in the exclusive jurisdiction of a court or forum other than the Court of Chancery, or for which the Court of Chancery does not have subject matter jurisdiction. Any person or entity purchasing or otherwise acquiring any interest in shares of capital stock of the Corporation shall be deemed to have notice of and consented to the provisions of this Article TENTH.

ELEVENTH: In furtherance and not in limitation of the rights, powers, privileges and discretionary authority granted or conferred by the DGCL or other statutes or laws of the State of Delaware, the Board of Directors is expressly authorized:

To make, amend, alter or repeal the Bylaws;

To authorize and cause to be executed mortgages and liens upon the real and personal property of the Corporation;

To set apart out of any funds of the Corporation available for dividends, a reserve or reserves for any proper purpose and to reduce any such reserve in the manner in which it was created; and

To adopt from time to time Bylaw provisions with respect to indemnification of directors, officers, employees, agents and other persons as it shall deem expedient and in the best interests of the Corporation and to the extent permitted by law.

TWELFTH: The books of the Corporation may be kept (subject to any provision contained in the statutes) outside the State of Delaware at such place or places as may be designated from time to time by the Board of Directors or in the Bylaws.

THIRTEENTH: The Corporation reserves the right to amend, alter, change or repeal any provisions herein contained, in the manner now or hereafter prescribed by statute, and all rights, powers, privileges and discretionary authority granted or conferred herein upon stockholders or directors are granted subject to this reservation.