Exhibit 8.1

February 17, 2017

NGL Energy Partners LP

6120 S. Yale Avenue, Suite 805

Tulsa, Oklahoma 74136

Re: Form S-3 Registration Statement

Ladies and Gentlemen:

We have acted as special counsel to NGL Energy Partners LP, a Delaware limited partnership (the “Partnership”), in connection with the offer and sale by the Partnership of common units representing limited partner interests in the Partnership (the “Units”). The Units are included in the Partnership’s registration statement on Form S-3 filed by the Partnership with the Securities and Exchange Commission on February 15, 2017 (the “Registration Statement”), in connection with the registration of the Units under the Securities Act of 1933, as amended (the “Act”), and the prospectus supplement dated February 15, 2017 (the “Prospectus Supplement”) to the prospectus contained in the Registration Statement.

It is understood that the opinions set forth below are to be used only in connection with the offer, issuance and sale of the Units while the Registration Statement is in effect. This opinion may not be relied upon by you for any other purpose. The Registration Statement provides that the Units may be offered in amounts, at prices and on terms to be set forth in one or more prospectus supplements or free writing prospectuses.

This opinion is based on various facts and assumptions, and is conditioned upon certain representations made by the Partnership as to factual matters through a letter certified by an officer of NGL Energy Holdings LLC, the general partner of the Partnership (the “Officer’s Certificate”). In addition, this opinion is based upon the factual representations of the Partnership concerning its business, properties and governing documents set forth in the Registration Statement. For purposes of our opinion, we have not made an independent investigation or audit of the facts set forth in the above-referenced documents or in the Officer’s Certificate. In addition, in rendering this opinion we have assumed the truth and accuracy of all representations and statements made to us that are qualified as to knowledge or belief, without regard to such qualification.

Our opinion relates only to the federal income tax matters addressed herein, and we express no opinion with respect to any other federal laws or any foreign laws, the laws of any state or any other jurisdiction or as to any matters of municipal law or the laws of any other local agencies within any state. We hereby confirm that all statements of legal conclusions contained in the discussion in the Registration Statement under the caption “Material U.S. Federal Income Tax Considerations,” as updated by the discussion in the Prospectus Supplement under the caption “Material U.S. Federal Income Tax Considerations Supplement,” insofar as such statements purport to constitute summaries of U.S. federal income tax law and regulations or legal conclusions with respect thereto, constitute the opinion of Winston & Strawn LLP with respect to the material U.S. federal income tax matters set forth therein as of the date of the Prospectus Supplement, subject to the assumptions, qualifications, and limitations set forth therein and in the Officer’s Certificate and excepting the representations and statements of fact of the Partnership and its general partner included in the discussion, as to which we express no opinion.

This opinion letter is limited to the matters set forth herein, and no opinions are intended to be implied or may be inferred beyond those expressly stated herein. Our opinion is rendered as of the date of the Prospectus Supplement and we assume no obligation to update or supplement this opinion or any matter related to this opinion to reflect any change of fact, circumstances, or law after the date of the Prospectus Supplement. This opinion is based on various statutory provisions, regulations promulgated thereunder and interpretations thereof by the Internal Revenue Service and the courts having jurisdiction over such matters, all of which are subject to change either prospectively or retroactively. Any variation or difference in the facts from those set forth in the representations described above, including the Registration Statement and the Officer’s Certificate, may affect the conclusions stated herein. In addition, our opinion is based on the assumption that the matter will be properly presented to the applicable court.

Furthermore, our opinion is not binding on the Internal Revenue Service or a court. In addition, we must note that our opinion represents merely our best legal judgment on the matters presented and that others may disagree with our conclusion. There can be no assurance that the Internal Revenue Service will not take a contrary position or that a court would agree with our opinion if litigated.

We hereby consent to the filing of this opinion as an exhibit to the Current Report on Form 8-K of the Partnership filed on or about the date hereof and to the reference to our firm under the captions “Material U.S. Federal Income Tax Considerations” in the base prospectus included in the Registration Statement and “Material U.S. Federal Income Tax Considerations Supplement” in the Prospectus Supplement. In giving this consent, we do not thereby admit that we are within the category of persons whose consent is required under Section 7 of the Act and the rules and regulations thereunder.