Exhibit 3.1

AMENDED AND RESTATED

CERTIFICATE OF INCORPORATION

OF

GOLDMAN SACHS MIDDLE MARKET LENDING CORP.

a Delaware corporation

1. Name. The name of the Corporation is Goldman Sachs Middle Market Lending Corp.

2. Registered Office and Agent. The address of the Corporation’s registered office in the State of Delaware is The Corporation Trust Company, Corporation Trust Center, 1209 Orange Street, Wilmington, New Castle County, DE 19801. The name of the Corporation’s registered agent at such address is The Corporation Trust Company.

3. Purpose. The purposes for which the Corporation is formed are to engage in any lawful act or activity for which corporations may be organized under the Delaware General Corporation Law and to possess and exercise all of the powers and privileges granted by such law and any other law of Delaware.

4. Authorized Capital. The aggregate number of shares of stock which the Corporation shall have authority to issue is One Hundred (100) shares, all of which are of one class and are designated as Common Stock and each of which has a par value of $0.01. Except as otherwise provided by law, the Common Stock shall have the exclusive right to vote for the election of directors and for all other purposes. Each share of Common Stock shall have one vote, and the Common Stock shall vote together as a single class.

5. Bylaws. The board of directors of the Corporation is authorized to adopt, amend or repeal the bylaws of the Corporation, except as otherwise specifically provided therein.

6. Elections of Directors. Elections of directors need not be by written ballot unless the bylaws of the Corporation shall so provide.

7. Right to Amend. The Corporation reserves the right to amend any provision contained in this Certificate as the same may from time to time be in effect in the manner now or hereafter prescribed by law, and all rights conferred on stockholders or others hereunder are subject to such reservation.

8. Limitation on Liability. The directors of the Corporation shall be entitled to the benefits of all limitations on the liability of directors generally that are now or hereafter become available under the Delaware General Corporation Law. Without limiting the generality of the foregoing, no director of the Corporation shall be 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 Delaware General Corporation Law, or (iv) for any transaction from which the director derived an improper personal benefit. Any repeal or modification of this Section 8 shall be prospective only, and shall not affect, to the detriment of any director, any limitation on the personal liability of a director of the Corporation existing at the time of such repeal or modification.

9. Business Combinations with Interested Stockholders. The Corporation elects not to be governed by Section 203 of the Delaware General Corporation Law.

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