Exhibit 5.1

[Jones Day Letterhead]

May 13, 2015

Eastman Chemical Company

200 South Wilcox Drive

Kingsport, Tennessee 37662

Re: Registration Statement on Form S-3 Filed by Eastman Chemical Company

Ladies and Gentlemen:

We have acted as counsel for Eastman Chemical Company, a Delaware corporation (the “Company”), in connection with the authorization of the issuance and sale from time to time, on a delayed basis, by the Company of an indeterminate amount of: (i) shares of common stock, par value $0.01 per share, of the Company (the “Common Stock”); (ii) shares of preferred stock, par value $0.01 per share, of the Company (the “Preferred Stock”), in one or more series, certain of which may be convertible into or exchangeable for Common Stock; (iii) depositary shares of the Company representing fractional interests in Preferred Stock of any series (the “Depositary Shares”); (iv) debt securities of the Company (the “Debt Securities”), in one or more series, certain of which may be convertible into or exchangeable for Common Stock; (v) warrants to purchase Common Stock, Preferred Stock or Debt Securities (the “Warrants”); (vi) stock purchase contracts to purchase Common Stock or Preferred Stock as may be designated at the time of the offering at a future date or dates (the “Stock Purchase Contracts”); and (vii) units consisting of one or more of the securities described in clauses (i) through (vi) above or securities or obligations of third parties (the “Units”), in each case, as contemplated by the Registration Statement on Form S-3 to which this opinion has been filed as an exhibit (the “Registration Statement”). The Common Stock, the Preferred Stock, the Depositary Shares, the Debt Securities, the Warrants, the Stock Purchase Contracts and the Units are collectively referred to herein as the “Securities.” The Securities may be offered and sold from time to time pursuant to Rule 415 under the Securities Act of 1933 (the “Securities Act”).

In connection with the opinions expressed herein, we have examined such documents, records and matters of law as we have deemed relevant or necessary for purposes of this opinion. Based on the foregoing, and subject to the further limitations, qualifications and assumptions set forth herein, we are of the opinion that:

1. The shares of Common Stock, upon receipt by the Company of such lawful consideration therefor having a value not less than the par value thereof as the Company’s Board of Directors (or an authorized committee thereof) may determine, will be validly issued, fully paid and nonassessable.

Eastman Chemical Company

May 13, 2015

Page 2

2. The shares of Preferred Stock, upon receipt by the Company of such lawful consideration therefor having a value not less than the par value thereof as the Company’s Board of Directors (or an authorized committee thereof) may determine, will be validly issued, fully paid and nonassessable.

3. The Depositary Shares, upon receipt by the Company of such lawful consideration therefor as the Company’s Board of Directors (or an authorized committee thereof) may determine, will be validly issued, and the depositary receipts representing the Depositary Shares will entitle the holders thereof to the rights specified therein and in the deposit agreement pursuant to which they are issued.

4. The Debt Securities, upon receipt by the Company of such lawful consideration therefor as the Company’s Board of Directors (or an authorized committee thereof) may determine, will constitute valid and binding obligations of the Company.

5. The Warrants, upon receipt by the Company of such lawful consideration therefor as the Company’s Board of Directors (or an authorized committee thereof) may determine, will constitute valid and binding obligations of the Company.

6. The Stock Purchase Contracts, upon receipt by the Company of such lawful consideration therefor as the Company’s Board of Directors (or an authorized committee thereof) may determine, will constitute valid and binding obligations of the Company.

7. The Units, upon receipt by the Company of such lawful consideration therefor as the Company’s Board of Directors (or an authorized committee thereof) may determine, will constitute valid and binding obligations of the Company.

In rendering the foregoing opinions, we have assumed that: (i) the Registration Statement, and any amendments thereto, will have become effective (and will remain effective at the time of issuance of any Securities thereunder); (ii) a prospectus supplement describing each class or series of Securities offered pursuant to the Registration Statement, to the extent required by applicable law and relevant rules and regulations of the Securities and Exchange Commission (the “Commission”), will be timely filed with the Commission; (iii) the definitive terms of each class or series of Securities will have been established in accordance with the authorizing resolutions adopted by the Company’s Board of Directors (or an authorized committee thereof), the Company’s Amended and Restated Certificate of Incorporation (the “Certificate of Incorporation”) and applicable law; (iv) the Company will issue and deliver the Securities in the manner contemplated by the Registration Statement and any Securities issuable upon conversion, exchange or exercise of any other Security, will have been authorized and reserved for issuance, in each case within the limits of the then remaining authorized but unreserved and unissued amounts of such Securities; (v) the resolutions authorizing the Company to issue, offer and sell the Securities will have been adopted by the Company’s Board of Directors (or an authorized committee thereof) and will be in full force and effect at all times at which the Securities are offered or sold by the Company; (vi) all Securities will be issued in compliance with applicable federal and state securities laws; and (vii) any Indenture, Depositary Share Agreement, Warrant Agreement, Stock Purchase Contract Agreement or Unit Agreement (each as defined below) and each Unit will be governed by and construed in accordance with the laws of the State of New York.

Eastman Chemical Company

May 13, 2015

Page 3

With respect to any Securities consisting of any series of Debt Securities, we have further assumed that: (i) such Debt Securities will have been issued pursuant to an indenture that has been executed and delivered by the Company and the applicable trustee in a form approved by us (the “Indenture”), and the Indenture will have been qualified under the Trust Indenture Act of 1939; (ii) all terms of such Debt Securities not provided for in the applicable Indenture will have been established in accordance with the provisions of the applicable Indenture and reflected in appropriate documentation approved by us and, if applicable, executed and delivered by the Company and the applicable trustee; and (iii) such Debt Securities will be executed, authenticated, issued and delivered in accordance with the provisions of the applicable Indenture.

With respect to any Securities consisting of Preferred Stock, we have further assumed that the Company will issue and deliver the shares of the Preferred Stock being issued and delivered after the filing with the Secretary of State of the State of Delaware of a certificate of amendment to the Certificate of Incorporation, approved by us, establishing the designations, preferences and rights of the class or series of the Preferred Stock being issued and delivered.

With respect to any Securities consisting of Depositary Shares, we have further assumed that the Depositary Shares will be: (i) issued and delivered after authorization, execution and delivery of the deposit agreement, approved by us, relating to the Depositary Shares to be entered into between the Company and an entity (the “Depositary”) selected by the Company to act as depository (the “Depositary Share Agreement”); and (ii) issued after the Company deposits with the Depositary shares of the Preferred Stock to be represented by such Depositary Shares that are authorized, validly issued and fully paid as contemplated by the Registration Statement and the Depositary Share Agreement.

With respect to any Securities consisting of Warrants, we have further assumed that: (i) the warrant agreement, approved by us, relating to the Warrants (the “Warrant Agreement”) to be entered into between the Company and an entity selected by the Company to act as the warrant agent (the “Warrant Agent”) will have been authorized, executed and delivered by the Company and the Warrant Agent; and (ii) the Warrants will be authorized, executed and delivered by the Company and the Warrant Agent in accordance with the provisions of the Warrant Agreement.

With respect to any Securities consisting of Stock Purchase Contracts, we have further assumed that: (i) the stock purchase contract agreement, approved by us, relating to the Stock Purchase Contracts (the “Stock Purchase Contract Agreement”) to be entered into between the Company and an entity selected by the Company to act as the stock purchase contract agent (the “Stock Purchase Contract Agent”) will have been authorized, executed and delivered by the Company and the Stock Purchase Contract Agent; and (ii) the Stock Purchase Contracts will be authorized, executed and delivered by the Company and the Stock Purchase Contract Agent in accordance with the provisions of the Stock Purchase Contract Agreement.

Eastman Chemical Company

May 13, 2015

Page 4

With respect to any Securities consisting of Units, we have further assumed that each component of such Units will be authorized, validly issued and fully paid (to the extent applicable) as contemplated by the Registration Statement and the applicable unit agreement (the “Unit Agreement”), if any.

Our opinions set forth in paragraphs 4, 5, 6 and 7 are limited by bankruptcy, insolvency, reorganization, fraudulent transfer and fraudulent conveyance, voidable preference, moratorium or other similar laws and related regulations and judicial doctrines from time to time in effect relating to or affecting creditors’ rights generally, and by general equitable principles and public policy considerations, whether such principles and considerations are considered in a proceeding at law or at equity.

As to facts material to the opinions and assumptions expressed herein, we have relied upon oral and written statements and representations of officers and other representatives of the Company and others. The opinions expressed herein are limited to the laws of the State of New York and the General Corporation Law of the State of Delaware, in each case as currently in effect, and we express no opinion as to the effect of the laws of any other jurisdiction.

We hereby consent to the filing of this opinion as Exhibit 5 to the Registration Statement and to the reference to Jones Day under the caption “Validity of Securities” in the prospectus constituting a part of such Registration Statement. In giving such consent, we do not thereby admit that we are included in 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 Day