Exhibit 5.1

March 18, 2015

Board of Directors

Walker & Dunlop, Inc.

7501 Wisconsin Avenue

Suite 1200E

Bethesda, MD 20814

Ladies and Gentlemen:

We are acting as counsel to Walker & Dunlop, Inc., a Maryland corporation (the “Company”), in connection with the sale of 8,246,534 of shares of common stock of the Company, par value $0.01 per share, by FIF V WD LLC, FCOF UB Investments LLC, FCOF II UB Investments LLC, FTS SIP LP, FCO MA II UB Securities LLC and FCO MA LSS LP, as selling shareholders, pursuant to a prospectus supplement dated March 16, 2015 and the accompanying prospectus dated November 30, 2012 (such documents, collectively, the “Prospectus”) that form a part of the Company’s effective shelf registration statement on Form S-3 (File 333-184297), filed with the Securities and Exchange Commission (the “Commission”) on October 4, 2012 (the “Registration Statement”). This opinion letter is furnished to you at your request to enable you to fulfill the requirements of Item 601(b)(5) of Regulation S-K, 17 C.F.R. § 229.601(b)(5).

For purposes of this opinion letter, we have examined copies of such agreements, instruments and documents as we have deemed an appropriate basis on which to render the opinions hereinafter expressed. In our examination of the aforesaid documents, we have assumed the genuineness of all signatures, the legal capacity of all natural persons, the accuracy and completeness of all documents submitted to us, the authenticity of all original documents, and the conformity to authentic original documents of all documents submitted to us as copies (including telecopies). As to all matters of fact, we have relied on the representations and statements of fact made in the documents so reviewed, and we have not independently established the facts so relied on. This opinion letter is given, and all statements herein are made, in the context of the foregoing.

This opinion letter is based as to matters of law solely on the Maryland General Corporation Law, as amended. We express no opinion herein as to any other laws, statutes, ordinances, rules, or regulations.

Based upon, subject to and limited by the foregoing, we are of the opinion that the Shares are validly issued, fully paid, and nonassessable.

This opinion letter has been prepared for use in connection with the sale described above. We assume no obligation to advise you of any changes in the foregoing subsequent to the date hereof.

We hereby consent to the filing of this opinion letter as Exhibit 5.1 to the Company’s Current Report on Form 8-K to be filed by the Company with the Commission and the incorporation thereof by reference into the Registration Statement and to the reference to this firm under the caption “Legal Matters” in the Prospectus. In giving this consent, we do not thereby admit that we are an “expert” within the meaning of the Securities Act of 1933.

Very truly yours,

/s/ HOGAN LOVELLS US LLP

HOGAN LOVELLS US LLP

Hogan Lovells US LLP is a limited liability partnership registered in the District of Columbia. “Hogan Lovells” is an international legal practice that includes Hogan Lovells US LLP and Hogan Lovells International LLP, with offices in: Alicante Amsterdam Baltimore Beijing Brussels Caracas Colorado Springs Denver Dubai Dusseldorf Frankfurt Hamburg Hanoi Ho Chi Minh City Hong Kong Houston Johannesburg London Los Angeles Luxembourg Madrid Mexico City Miami Milan Monterrey Moscow Munich New York Northern Virginia Paris Philadelphia Rio de Janeiro Rome San Francisco São Paulo Shanghai Silicon Valley Singapore Tokyo Ulaanbaatar Warsaw Washington DC Associated offices: Budapest Jakarta Jeddah Riyadh Zagreb. For more information see www.hoganlovells.com