Exhibit 5.1

July 5, 2022

Earthstone Energy, Inc.

1400 Woodloch Forest Drive, Suite 300

The Woodlands, Texas 77380

Re:    Registration Statement on Form S-3

Ladies and Gentlemen:

We have acted as counsel to Earthstone Energy, Inc., a Delaware corporation (the “Company”), in connection with the preparation and filing with the U.S. Securities and Exchange Commission (the “Commission”) of a Registration Statement on Form S-3 (the “Registration Statement”) under the Securities Act of 1933, as amended (the “Securities Act”), relating to the registration under the Securities Act and the proposed offering and sale from time to time pursuant to Rule 415 under the Securities Act by the selling stockholders named therein (the “Selling Stockholders”), together or separately, of up to 19,417,476 shares (the “Shares”) of the Company’s Class A common stock, $0.001 par value per share.

We have examined signed copies of the Registration Statement filed with the Commission. We have also examined and relied upon resolutions of the Board of Directors of the Company, the Third Amended and Restated Certificate of Incorporation and Amended and Restated Bylaws of the Company, each as restated and/or amended to date, and such other documents as we have deemed necessary for purposes of rendering the opinions hereinafter set forth.

In our examination of the foregoing documents, we have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as originals, the conformity to original documents of all documents submitted to us as copies, the authenticity of the originals of such latter documents, and the legal competence of all signatories to such documents.

Based on the foregoing, and subject to the assumptions, qualifications, limitations, and exceptions set forth herein, we are of the opinion that the Shares have been duly authorized and are validly issued, fully paid and nonassessable.

The foregoing opinion is limited in all respects to the General Corporation Law of the State of Delaware (including the applicable provisions of the Delaware Constitution and the reported judicial decisions interpreting these laws) and the federal laws of the United States of America, and we do not express any opinions as to the laws of any other jurisdiction, domestic or foreign.

Please note that we are opining only as to the matters expressly set forth herein, and no opinion should be inferred as to any other matters. This Opinion Letter is based upon currently existing statutes, rules, regulations and judicial decisions, and we disclaim any obligation to advise you of any change in any of these sources of law or subsequent legal or factual developments which might affect any matters or opinions set forth herein.

We hereby consent to the filing of this Opinion Letter as an exhibit to the Registration Statement and to the references to our firm under the caption “Legal Matters” in the prospectus forming a part of the Registration Statement. In giving our consent, we do not admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission promulgated thereunder.

Very truly yours,

/s/ Jones & Keller, P.C.