Exhibit 5.1

July 2, 2014
	Fulbright & Jaworski LLP
	2200 Ross Avenue, Suite 2800
	Dallas, Texas 75201-2784
	United States
	Tel +1 214 855 8000
	Fax +1 214 855 8200
	nortonrosefulbright.com

Eclipse Resources Corporation

2121 Old Gatesburg Road, Suite 110

State College, Pennsylvania 16803

Re: Registration Statement on Form S-1

Ladies and Gentlemen:

We have acted as special counsel to Eclipse Resources Corporation, a Delaware corporation (the “Company”), in connection with the Company’s registration under the Securities Act of 1933, as amended (the “Act”), of the offer and sale of an aggregate of up to 16,000,000 shares of the Company’s common stock, par value $0.01 (the “Common Stock”), pursuant to the Company’s Registration Statement on Form S-8 (the “Registration Statement”) to be filed with the Securities and Exchange Commission on July 2, 2014, which shares of Common Stock may be issued from time to time in accordance with the terms of the Eclipse Resources Corporation 2014 Long-Term Incentive Plan (as amended from time to time, the “Plan”).

In reaching the opinions set forth herein, we have examined and are familiar with originals or copies, certified or otherwise identified to our satisfaction, of such documents and records of the Company and such statutes, regulations and other instruments as we deemed necessary or advisable for purposes of this opinion, including (i) the Registration Statement, (ii) certain resolutions adopted by the board of directors of the Company, (iii) the Plan, and (iv) such other certificates, instruments, and documents as we have considered necessary for purposes of this opinion letter. As to any facts material to our opinions, we have made no independent investigation or verification of such facts and have relied, to the extent that we deem such reliance proper, upon certificates of public officials and officers or other representatives of the Company.

We have assumed (i) the legal capacity of all natural persons, (ii) the genuineness of all signatures, (iii) the authority of all persons signing all documents submitted to us on behalf of the parties to such documents, (iv) the authenticity of all documents submitted to us as originals, (v) the conformity to authentic original documents of all documents submitted to us as copies, (vi) that all information contained in all documents reviewed by us is true, correct, and complete, and (vii) that the shares of Common Stock will be issued in accordance with the terms of the Plan.

Fulbright & Jaworski LLP is a limited liability partnership registered under the laws of Texas.

Fulbright & Jaworski LLP, Norton Rose Fulbright LLP, Norton Rose Fulbright Australia, Norton Rose Fulbright Canada LLP, Norton Rose Fulbright South Africa (incorporated as Deneys Reitz, Inc.), each of which is a separate legal entity, are members of Norton Rose Fulbright Verein, a Swiss Verein. Details of each entity, with certain regulatory information, are at nortonrosefulbright.com. Norton Rose Fulbright Verein helps coordinate the activities of the members but does not itself provide legal services to clients.

July 2, 2014

Page 2

Based on the foregoing and subject to the limitations set forth herein, and having due regard for the legal considerations we deem relevant, we are of the opinion that the shares of Common Stock have been duly authorized and, when the shares of Common Stock are issued by the Company in accordance with the terms of the Plan and the instruments executed pursuant to the Plan, as applicable, which govern the awards to which shares of Common Stock relate, the shares of Common Stock will be validly issued, fully paid, and non-assessable.

This opinion is limited in all respects to the federal laws of the United States of America and the General Corporation Law of the State of Delaware. We express no opinion as to any matter other than as expressly set forth above, and no opinion on any other matter may be inferred or implied herefrom. The opinions expressed herein are rendered as of the date hereof, and we expressly disclaim any obligation to update this letter or advise you of any change in any matter after the date hereof.

The opinions expressed herein are rendered to you in connection with the Registration Statement and may be relied upon by you and by persons entitled to rely upon them pursuant to the applicable provisions of the Act. The opinions expressed herein may not be relied upon by you or any other person, firm or corporation for any other purpose.

This opinion letter may be filed as an exhibit to the Registration Statement. In giving this consent, we do not thereby admit that we come within the category of persons whose consent is required under Section 7 of the Act.

Very truly yours,

/s/ Fulbright & Jaworski LLP

FULBRIGHT & JAWORSKI LLP