Exhibit 5.1

Atlas Growth Partners, L.P.

Park Place Corporate Center One

1000 Commerce Drive, Suite 410

Pittsburgh, PA 15275

Ladies and Gentlemen:

We have acted as counsel to Atlas Growth Partners, L.P., a Delaware limited partnership (the “Partnership”), in connection with the preparation and filing with the U.S. Securities and Exchange Commission (the “Commission”), pursuant to the Securities Act of 1933, as amended (the “Securities Act”), of the registration statement on Form S-1, initially filed with the Commission on October 21, 2015 (File No. 333-207537) (as amended, the “Registration Statement”), including the prospectus included as part of the Registration Statement (the “Prospectus”). The Registration Statement relates to the continuous offering from time to time, pursuant to Rule 415 of the rules and regulations promulgated under the Securities Act, of:

As such counsel and for purposes of our opinions set forth below, we have examined originals or copies, certified or otherwise identified to our satisfaction, of such documents, corporate records, certificates of public officials and other instruments as we have deemed necessary or appropriate as a basis for the opinions set forth herein, including, without limitation:

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In addition to the foregoing, we have made such investigations of law as we have deemed necessary or appropriate as a basis for the opinions set forth herein.

We have also examined originals or copies, certified or otherwise identified to our satisfaction, of such records of the Partnership and the General Partner and such agreements, certificates of public officials, certificates of officers or other representatives of the Partnership Entities and others, and such other documents, certificates and records, as we have deemed necessary or appropriate as a basis for the opinions set forth herein. In addition to the foregoing, we have made such investigations of law as we have deemed necessary or appropriate as a basis for the opinions set forth herein.

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In such examination and in rendering the opinions expressed below, we have assumed, without independent investigation or verification: (i) the legal capacity and authority of all natural persons or entities (other than the Partnership and the General Partner) executing all agreements, instruments, books and records, certificates and other documents submitted to us; (ii) the due authorization, execution and delivery of all agreements, instruments, books and records, certificates and other documents by all parties thereto (other than the Partnership and the General Partner); (iii) the genuineness of all signatures on all agreements, instruments, books and records, certificates and other documents submitted to us; (iv) the authenticity and completeness of all agreements, instruments, books and records, certificates and other documents submitted to us as originals; (v) that all agreements, instruments, books and records, certificates and other documents submitted to us as certified, electronic, facsimile, conformed, photostatic or other copies conform to originals thereof and that such originals are authentic and complete; (vi) that no documents submitted to us have been amended or terminated orally or in writing except as has been disclosed to us in writing; (vii) that the statements contained in the certificates and comparable documents of public officials, officers and representatives of the Partnership and other persons on which we have relied for the purposes of this opinion letter are true and correct; (viii) that there has not been any change in the good standing status of the Partnership or the General Partner from that reported in the certificate of good standing regarding the Partnership and the General Partner obtained from the Delaware Secretary of State; (ix) that each of the officers, members, partners and members of the board of directors or other governing body of the Partnership has properly exercised his or her fiduciary duties; (x) that no such documents submitted to us have been amended or terminated orally or in writing except as has been disclosed to us; (xi) that the Pre-Listing Partnership Agreement will be in full force and effect and will not have been amended as of the date on which the Primary Offering Securities are issued by the Partnership; (xii) that there are no agreements or understandings between or among the parties to the Pre-Listing Partnership Agreement, the Subscription Agreements and the Warrant Agreements or third parties (other than the Partnership and the General Partner with respect to the Pre-Listing Partnership Agreement, the Subscription Agreements and the Warrant Agreements) that would expand, modify or otherwise affect the terms of the Pre-Listing Partnership Agreement, the Subscription Agreements or the Warrant Agreements, as applicable, or the respective rights or obligations of the parties thereunder; (xiii) that the books and records of the Partnership will set forth all information required by the Existing Partnership Agreement, the Pre-Listing Agreement and the Delaware Revised Uniform Limited Partnership Act (6 Del. C. § 17-101, et seq.) (the “LP Act”), including all information with respect to each holder of a Pre-Listing Unit (each, a “Pre-Listing Unit Holder” and collectively, the “Pre-Listing Unit Holders”), and their contributions to the Partnership; (xiv) that the payment or exchange by each purchaser of Primary Offering Securities of the full consideration due for the Primary Offering Securities acquired by such purchaser; (xv) that the Pre-Listing Unit Holders will fulfill all of their obligations set forth in the Pre-Listing Partnership Agreement; and (xvi) that upon a Listing Event, the Post-Listing Partnership Agreement will be in full force and effect and will not have been amended as of the date on which the Post-Listing Common Units are issued by the Partnership.

As to all questions of fact material to this opinion letter, and as to the materiality of any fact or other matter referred to herein, we have relied (without independent investigation) upon certificates or comparable documents of officers and representatives of the Partnership and the General Partner.

Based upon the foregoing, and in reliance thereon, and subject to the limitations, qualifications and exceptions set forth herein, we are of the following opinions:

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With respect to the opinions set forth in paragraphs 2 and 4 above, the term “purchasers of such common units” does not include a person or entity that is or was a general partner of the Partnership.

Without limiting any of the other limitations, exceptions and qualifications stated elsewhere herein, we express no opinion with regard to the applicability or effect of the laws of any jurisdiction other than (i) the LP Act and (ii) the Delaware Limited Liability Company Act, in each case as in effect on the date of this opinion letter and as interpreted by the courts of the State of Delaware.

This opinion letter deals only with the specified legal issues expressly addressed herein, and you should not infer any opinion that is not explicitly addressed herein from any matter stated in this opinion letter.

This opinion letter is rendered solely in connection with the Registration Statement. This opinion letter is rendered as of the date hereof, and we assume no obligation to advise you or any other person with regard to any change after the date hereof in the circumstances or the law that may bear on the matters set forth herein even if the change may affect the legal analysis or a legal conclusion or other matters in this opinion letter. We hereby consent to the filing of this opinion with the Commission as Exhibit 5.1 to the Registration Statement and to the reference to our firm under the heading “Legal Matters” in the Prospectus. In giving such consent, we do not thereby 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 thereunder.