Exhibit 5.1

November 25, 2014

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 an additional 300,000 shares of common stock of the Company, par value $0.01 per share, pursuant to an option granted to Morgan Stanley & Co. LLC (the “Underwriter”) to purchase additional shares under the terms of the Underwriting Agreement, dated November 20, 2014, by and among the Company, the Underwriter and FIF V WD LLC, FCOF UB Investments LLC, FCOF II UB Investments LLC, FTS SIP L.P., FCO MA II UB Securities LLC and FCO MA LSS LP, as selling shareholders, pursuant to a prospectus supplement dated November 20, 2014 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 on November 30, 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. As used herein, the term “Maryland General Corporation Law, as amended” includes the statutory provisions contained therein, all applicable provisions of the Maryland Constitution and reported judicial decisions interpreting these laws.

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 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   Berlin   Brussels   Caracas   Colorado Springs   Denver   Dubai   Dusseldorf   Frankfurt   Hamburg   Hanoi   Ho Chi Minh City   Hong Kong   Houston   London   Los Angeles   Madrid   Miami   Milan   Moscow   Munich   New York   Northern Virginia   Paris   Philadelphia   Prague   Rome   San Francisco   Shanghai   Silicon Valley   Singapore   Tokyo   Ulaanbaatar   Warsaw   Washington DC   Associated offices: Budapest   Jakarta   Jeddah   Riyadh   Zagreb. For more information see www.hoganlovells.com

- 2 -