EX-3.1

Exhibit 3.1

AMENDED AND RESTATED

CERTIFICATE OF INCORPORATION

Reata Pharmaceuticals, Inc.

(a Delaware Corporation)

ARTICLE ONE

The name of the corporation (hereinafter called the “Corporation”) is Reata Pharmaceuticals, Inc.

ARTICLE TWO

The address, including street, number, city, and county, of the registered office of the Corporation in the State of Delaware is 1209 Orange Street, Wilmington, 19801, County of New Castle, Delaware and the name of the registered agent of the Corporation in the State of Delaware at such address is The Corporation Trust Company.

ARTICLE THREE

The purpose of the Corporation is to engage in any lawful act or activity for which a corporation may now or hereafter be organized under the General Corporation Law of the State of Delaware (the “DGCL”).

ARTICLE FOUR

The aggregate number of shares which the Corporation shall have authority to issue is 1,000 shares of Common Stock, par value $0.001 per share.

ARTICLE FIVE

5.1 Meetings.

(a) Except as otherwise required by law or regulation, the annual meeting of the stockholders of the Corporation for the election of directors and for the transaction of such other business as may properly come before the meeting shall be held at such date, time and place, if any, as shall be determined solely by the resolution of the board of directors of the Corporation (the “Board”) in its sole and absolute discretion. After the closing of the first underwritten public offering by the Corporation that results in its Class A Common Stock being listed for trading on a U.S. national securities exchange, any action required or permitted to be taken by the stockholders of the Corporation must be effected at a duly called annual or special meeting of stockholders of the Corporation and may not be effected by any consent in writing by such stockholders.

(b) Special meetings of the stockholders of the Corporation, and any proposals to be considered at such meetings, may be called and proposed exclusively by the Board in its sole and absolute discretion, pursuant to a resolution approved by a majority of the members of the Board serving at the time of such vote, and no stockholder of the Corporation shall require the Board to call a special meeting of the stockholders or to propose business at a special meeting of the stockholders.

(c) Except as otherwise required by law or regulation, no business proposed by a stockholder to be considered at an annual meeting of the stockholders (including the nomination of any person to be elected as a director of the Corporation) will be considered by the stockholders at that meeting unless, no earlier than one hundred and twenty (120) days before and no later than ninety (90) days before the anniversary of the preceding year’s annual meeting of stockholders; provided, however, that if the date of the annual meeting is more than thirty (30) days before or more than sixty (60) days after the anniversary of the preceding year’s annual meeting, then such dates shall be not earlier than one hundred and twenty (120) days before the date of the annual meeting and not later than the later of one hundred (100) days before the date of the annual meeting and ten (10) days after the first public announcement of the date set for that meeting is made, whether or not such first public announcement constitutes notice of the meeting to stockholders, the Corporation receives from the stockholder proposing that business a written notice that sets forth: (1) the nature of the proposed business with reasonable particularity, including the exact text of any proposal to be presented for adoption, and the reasons for conducting that business at the annual meeting; (2) with respect to each such stockholder, that stockholder’s name and address (as they appear on the records of the Corporation), business address and telephone number, residence address and telephone number, and the number of shares of each class of stock of the Corporation beneficially owned by that stockholder; (3) any interest of the stockholder in the proposed business; (4) the name or names of each person nominated by the stockholder to be elected or re-elected as a director, if any; and (5) with respect to each nominee, that nominee’s name, business address and telephone number, and residence address and telephone number, the number of shares, if any, of each class of stock of the Corporation owned directly and beneficially by that nominee, and all information relating to that nominee that is required to be disclosed in solicitations of proxies for elections of directors, or is otherwise required, pursuant to Regulation 14A under the Exchange Act, as amended, or any provision of law subsequently replacing Regulation 14A, together with a duly acknowledged letter signed by the nominee stating his or her acceptance of the nomination by that stockholder, stating his or her intention to serve as a director if elected, and consenting to being named as a nominee for director in any proxy statement relating to such election. Notwithstanding the foregoing provisions of this Section 5.1(c), unless otherwise

required by law, if the stockholder (or a qualified representative of the stockholder) does not appear at the annual meeting of stockholders to present a nomination or proposed business, such nomination shall be disregarded and such proposed business shall not be transacted, notwithstanding that proxies to vote in respect of such matters may have been received by the Corporation. The Bylaws of the Corporation may require a nominee for election as a director, a stockholder giving the notice proposing a nomination or business, or a beneficial owner on whose behalf a nomination or proposal is made, to provide information in addition to any information required by this Certificate and to comply with any requirements in addition to any requirement in this Certificate. The person presiding at the annual meeting will determine whether business (including the nomination of any person as a director) has been properly brought before the meeting and, if the facts so warrant, will not permit any business (or voting with respect to any particular nominee) to be transacted that has not been properly brought before the meeting.

5.2 Number of directors.

The business and affairs of the Corporation shall be managed by and under the direction of the Board. The total number of directors constituting the Board shall be fixed by the Board by a resolution adopted by a majority of the members of the Board serving at the time of such vote.

5.3 Classes of directors.

The directors shall be divided, with respect to the time for which they severally hold office, into three classes, as nearly equal in number as is reasonably possible, with the initial term of office of the first class to expire at the annual meeting of the stockholders of the Corporation held in 2016 (the “Class I Directors”), the initial term of office of the second class to expire at the annual meeting of the stockholders of the Corporation held in 2017 (the “Class II Directors”), and the initial term of office of the third class to expire at the annual meeting of the stockholders of the Corporation held in 2018 (the “Class III Directors”), with each director to hold office until his successor shall have been duly elected and qualified. At each annual meeting of stockholders, directors elected to succeed those directors whose terms then expire shall be elected for a term of office to expire at the third succeeding annual meeting of stockholders after their election, with each director to hold office until his successor shall have been duly elected and qualified. The Board is authorized to assign members of the Board already in office to Class I, Class II or Class III to be effective at the time such classification becomes effective. If the number of directors that constitutes the whole Board is changed as permitted by this Article, the majority of the members of the Board serving at the time of the vote to make such change shall also fix and determine the number of directors comprising each class; provided, however, that any increase or decrease in the number of directors shall be apportioned among the classes as equally as reasonably possible.

5.4 Election of directors.

Directors shall be elected by a plurality of the voting power of the outstanding shares of stock of the Corporation that are present in person or represented by proxy at the meeting duly called for such purpose and that are entitled to vote generally on the election of directors.

5.5 Vacancies.

Any newly created directorship that results from an increase in the number of directors or any vacancy on the Board that results from the death, disability, resignation, disqualification or removal of any director or from any other cause shall be filled solely by the affirmative vote of a majority of the members of the Board serving at the time of such vote, even if less than a quorum, or by a sole remaining director and shall not be filled by the stockholders. No decrease in the number of authorized directors constituting the Board shall shorten the term of any incumbent director. Each director chosen to fill a vacancy in the Board shall receive the classification of the vacant directorship to which he or she has been appointed or, if it is a newly created directorship, shall receive the classification that at least a majority of the members of the Board serving at the time of such vote designates and shall hold office until the first meeting of stockholders held after his or her appointment for the purpose of electing directors of that classification and until his or her successor is elected and qualified or until his or her earlier death, resignation or removal from office.

5.6 Removal.

No director of any class of directors of the Corporation shall be removed except for cause and by an affirmative vote of the holders of a majority of the voting power of the outstanding shares of stock of the Corporation entitled to vote generally on the election of directors, acting at a meeting of the stockholders in accordance with the DGCL, this Certificate and the Bylaws of the Corporation.

5.7 Committees.

The Board may designate and appoint from among its members one or more committees, which may have one or more members, and may designate one or more of its members as alternate members, who may, subject to any limitations imposed by the Board, replace absent or disqualified members at any meeting of such committee. The stockholders of the Corporation shall have no power to appoint or remove directors as members of committees of the Board, nor to abrogate the power of the Board to establish any such committees or the power of any such committee to exercise the powers and authority of the Board.

ARTICLE SIX

The Board will elect the officers of the Corporation, subject to the rights, if any, of an officer under any contract of employment, and subject to the power of the Board to delegate the election of one or more officers to a committee of the Board or to an officer or committee of officers. The Board may appoint or remove, or empower an officer to appoint or remove, such officers and agents of the business as the Corporation may require, each of whom will hold office for such period, have such authority, and perform such duties as described in the Bylaws of the Corporation or by resolution of the Board. Any vacancy occurring in any office of the Corporation will be filled by the Board or may be filled by the officer, if any, who appointed such officer. The stockholders of the Corporation shall have no power to elect or remove officers of the Corporation or to abrogate the power of the Board to elect and remove officers of the Corporation.

ARTICLE SEVEN

Except as otherwise provided in this Certificate, in furtherance and not in limitation of the powers conferred by statute, the Board is expressly authorized to adopt, amend or repeal in any respect any or all of the Bylaws of the Corporation. Any adoption, amendment or repeal of the Bylaws of the Corporation by the Board shall require the approval of a majority of the members of the Board serving at the time of that vote. The stockholders of the Corporation shall also have the power to adopt, amend or repeal the Bylaws of the Corporation; provided, however, that the affirmative vote of the holders of at least two-thirds (66 2/3%) of the voting power of the shares of capital stock of the Corporation issued and outstanding and entitled to vote generally on the election of directors shall be required to alter, amend or repeal any provision contained in the Bylaws of the Corporation in the event of such vote, and; provided further, that the Bylaws of the Corporation shall not contain any provision inconsistent with this Certificate.

ARTICLE EIGHT

Elections of directors need not be by written ballot unless the Bylaws of the Corporation shall so provide.

ARTICLE NINE

Meetings of stockholders of the Corporation may be held within or without the State of Delaware, as the Bylaws of the Corporation may provide. The books of the Corporation may be kept (subject to any provision of applicable law) outside the State of Delaware at such place or places as may be designated from time to time by the Board or in the Bylaws of the Corporation.

ARTICLE TEN

Unless the Corporation consents in writing to the selection of an alternative forum, the sole and exclusive forum for (i) any derivative action or proceeding brought on behalf of the Corporation, (ii) any action asserting a claim of breach of a fiduciary duty owed by any director, officer, other employee or agent or stockholder of the Corporation to the Corporation or the Corporation’s stockholders, (iii) any action against the Corporation arising pursuant to any provision of the DGCL or as to which the DGCL confers jurisdiction on the Court of Chancery of the State of Delaware, or (iv) any action against the Corporation or any director, officer, other employee or agent of the Corporation asserting a claim governed by the internal affairs doctrine, including, without limitation, any action to interpret, apply, enforce or determine the validity of this Certificate or the Bylaws of the Corporation (as they shall be amended from time to time), shall be the Court of Chancery of the State of Delaware (or if the Court of Chancery does not have jurisdiction, the federal district court for the District of Delaware), in each case subject to such Court of Chancery (or if the Court of Chancery does not have jurisdiction, the federal district court for the District of Delaware) having personal jurisdiction over the indispensable parties named as defendants therein. Any person or entity purchasing or otherwise acquiring any interest in shares of capital stock of the Corporation shall be deemed to have notice of and consented to the provisions of this Article Ten.

ARTICLE ELEVEN

A director of this Corporation shall not be personally liable to the Corporation or its stockholders for monetary damages for breach of fiduciary duty as a director, except for liability (i) for any breach of the director’s duty of loyalty to the Corporation or its stockholders, (ii) for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law, (iii) under Section 174 of the DGCL, or (iv) for any transaction from which the director derived an improper personal benefit. If the DGCL is amended to authorize the further elimination or limitation of the liability of directors, then the liability of a director of the Corporation, in addition to the limitation on personal liability provided in this Certificate, shall be eliminated or limited to the fullest extent permitted by the DGCL as so amended. No amendment to or repeal of this Article Eleven shall apply to or have any effect on the liability or alleged liability of any director of the Corporation for or with respect to any acts or omissions of such director occurring prior to such amendment or repeal.

ARTICLE TWELVE

No contract or transaction between the Corporation and one or more of its directors, officers or stockholders or between the Corporation and any other corporation, partnership, association or other organization in which one or more of its directors, officers or stockholders are directors, officers or stockholders, or have a financial interest, shall be void or voidable solely for this reason, or solely because the director or officer is

present at or participates in the meeting of the Board or committee which authorizes the contract or transaction, or solely because any such director’s or officer’s votes are counted for such purpose, if: (1) the material facts as to the director’s or officer’s relationship or interest and as to the contract or transaction are disclosed or are known to the Board or the committee, and the Board or committee in good faith authorizes the contract or transaction by the affirmative votes of a majority of the disinterested directors, even though the disinterested directors be less than a quorum; or (2) the material facts as to the director’s or officer’s relationship or interest and as to the contract or transaction are disclosed or are known to the stockholders entitled to vote generally on the election of directors, and the contract or transaction is specifically approved in good faith by a vote of the stockholders; or (3) the contract or transaction is fair as to the Corporation as of the time it is authorized, approved or ratified, by the Board, a committee or the stockholders. Common or interested directors may be counted in determining the presence of a quorum at a meeting of the Board or of a committee which authorizes the contract or transaction.

ARTICLE THIRTEEN

The Corporation shall indemnify any person who was, is or is threatened to be made a party to a proceeding (as hereinafter defined) by reason of the fact that he or she (i) is or was a director or officer of the Corporation or (ii) while a director or officer of the Corporation, is or was serving at the request of the Corporation as a director, officer, partner, venturer, proprietor, trustee, employee, agent, or similar functionary of another foreign or domestic corporation, partnership, joint venture, sole proprietorship, trust, employee benefit plan, or other enterprise, to the fullest extent permitted under the DGCL, as the same exists or may hereafter be amended. Such right shall be a contract right and as such shall inure to the benefit of any director or officer who is elected and accepts the position of director or officer of the Corporation or elects to continue to serve as a director or officer of the Corporation while this Article Thirteen is in effect. Any repeal or amendment of this Article Thirteen shall be prospective only and shall not limit the rights of any such director or officer or the obligations of the Corporation with respect to any claim arising from or related to the services of such director or officer in any of the foregoing capacities prior to any such repeal or amendment to this Article Thirteen. Such right shall include the right to be paid by the Corporation expenses (including without limitation attorneys’ fees) actually and reasonably incurred by him in defending any such proceeding in advance of its final disposition to the maximum extent permitted under the DGCL, as the same exists or may hereafter be amended. If a claim for indemnification or advancement of expenses hereunder is not paid in full by the Corporation within sixty (60) days after a written claim has been received by the Corporation, the claimant may at any time thereafter bring suit against the Corporation to recover the unpaid amount of the claim, and if successful in whole or in part, the claimant shall also be entitled to be paid the expenses of prosecuting such claim. It shall be a defense to any such action that such indemnification or advancement of costs of defense is not permitted under the DGCL, but the burden of proving such defense shall be on the Corporation. Neither the failure of the Corporation (including its Board or any committee thereof, independent legal counsel, or stockholders) to have made its determination prior to the commencement of such action that indemnification of, or advancement of costs of defense to, the claimant is permissible

in the circumstances nor any actual determination by the Corporation (including its Board or any committee thereof, independent legal counsel, or stockholders) that such indemnification or advancement is not permissible shall be a defense to the action or create a presumption that such indemnification or advance is not permissible. In the event of the death of any person having a right of indemnification under the foregoing provisions, such right shall inure to the benefit of his or her heirs, executors, administrators, and personal representatives. The rights conferred above shall not be exclusive of any other right which any person may have or hereafter acquire under any statute, bylaw, resolution of stockholders or directors, agreement or otherwise.

ARTICLE FOURTEEN

The Corporation reserves the right, subject to any express provisions or restrictions contained in this Certificate or the Bylaws of the Corporation, from time to time, to amend, alter, change, or repeal any provision contained in this Certificate, in the manner now or hereafter prescribed by applicable laws, and all rights conferred upon stockholders in this Certificate or any amendment hereof are granted subject to this reservation; provided, however, that, after the closing of the first underwritten public offering by the Corporation that results in its Class A Common Stock being listed for trading on a U.S. national securities exchange, the affirmative vote of the holders of at least two-thirds (66 2/3%) of the voting power of the shares of capital stock of the Corporation issued and outstanding and entitled to vote generally on the election of directors shall be required to alter, amend or repeal Articles Three, Five, Six, Seven, Eight, Nine, Ten, Eleven, Twelve, Thirteen or Fourteen or to adopt any provision inconsistent with such Article.