Exhibit 5.1

May 31, 2018

PBF Energy Inc.

One Sylvan Way, Second Floor

Parsippany, NJ 07054

Ladies and Gentlemen:

We have acted as counsel to PBF Energy Inc., a Delaware corporation (the “Company”), in connection with the preparation and filing with the Securities and Exchange Commission of the Company’s Registration Statement on Form S-8 (the “Registration Statement”), under the Securities Act of 1933, as amended (the “Act”), relating to the registration of the offer, issuance and sale by the Company of up to an additional 10,2000,000 shares of Class A common stock, par value $0.001 per share, of the Company (plus any additional shares of Class A common stock of the Company as may be offered or issued to prevent dilution resulting from stock splits, stock dividends or similar transactions, the “Shares”), which may be issued pursuant to the PBF Energy Inc. Amended and Restated 2017 Equity Incentive Plan (the “2017 Equity Plan”).

In so acting, we have examined originals or copies (certified or otherwise identified to our satisfaction) of (i) the Amended and Restated Certificate of Incorporation of the Company; (ii) the Amended and Restated Bylaws of the Company; (iii) the 2017 Equity Plan; and (iv) the Registration Statement. We also have examined the originals, or duplicates or certified or conformed copies, of such corporate and other records, agreements, documents and other instruments and have made such other investigations as we have deemed relevant and necessary in connection with the opinions hereinafter set forth. As to questions of fact material to this opinion, we have relied upon certificates or comparable documents of public officials and of officers and representatives of the Company.

In rendering the opinion set forth below, we have assumed the genuineness of all signatures, the legal capacity of natural persons, the authenticity of all documents submitted to us as originals, the conformity to original documents of all documents submitted to us as duplicates or certified or conformed copies and the authenticity of the originals of such latter documents.

Based on the foregoing, and subject to the qualifications stated herein, we are of the opinion that the Shares have been duly authorized and, when issued and delivered in accordance with the 2017 Equity Plan, will be validly issued, fully paid and non-assessable.

Attorneys involved in the preparation of this opinion are admitted to practice law in the State of New York and we do not purport to be experts on, or express any opinion herein concerning, any law other than the laws of the State of New York, the federal laws of the United States of America and the General Corporation Law of the State of Delaware.

We hereby consent to the filing of this opinion as an exhibit to the Registration Statement and to the use of our name under the caption “Legal Matters” in the prospectus included in the Registration Statement. 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 or the rules and regulations promulgated thereunder.

Very truly yours,

/s/ Kramer Levin Naftalis & Frankel LLP

KRAMER LEVIN NAFTALIS & FRANKEL LLP