Exhibit 3.1

AMENDED AND RESTATED

CERTIFICATE OF INCORPORATION

OF

ON24, INC.

a Delaware corporation

(Pursuant to Sections 242 and 245 of the

General Corporation Law of the State of Delaware)

ON24, Inc., (the “Corporation”) a corporation organized and existing under and by virtue of the provisions of the General Corporation Law of the State of Delaware (the “DGCL”),

DOES HEREBY CERTIFY:

1. That the name of this Corporation is ON24, Inc., which was originally incorporated pursuant to the DGCL on January 8, 1998 under the name NewsDirect, Inc.

2. The Amended and Restated Certificate of Incorporation of this Corporation attached hereto as Exhibit A, which is incorporated herein by this reference, and which restates, integrates and further amends the provisions of the Certificate of Incorporation of this Corporation, as previously amended and restated, has been duly adopted by this Corporation’s Board of Directors and by the stockholders in accordance with Sections 242 and 245 of the DGCL, with the approval of this Corporation’s stockholders having been given by written consent without a meeting in accordance with Section 228 of the DGCL.

IN WITNESS WHEREOF, this Corporation has caused this Amended and Restated Certificate of Incorporation to be signed by its duly authorized officer and the foregoing facts stated herein are true and correct.

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IN WITNESS WHEREOF, this Amended and Restated Certificate of Incorporation has been executed by a duly authorized officer of this Corporation on this 5th day of February, 2021.

[Signature Page to Amended and Restated Certificate of Incorporation]

EXHIBIT A

AMENDED AND RESTATED

CERTIFICATE OF INCORPORATION

OF

ON24, INC.

a Delaware corporation

ARTICLE I

The name of the corporation is ON24, Inc. (hereinafter referred to as the “Corporation”).

ARTICLE II

The address of the Corporation’s registered office in the State of Delaware is 251 Little Falls Drive, Wilmington, Delaware 19808, County of New Castle. The name of the Corporation’s registered agent at such address is Corporation Service Company.

ARTICLE III

The purpose of the Corporation is to engage in any lawful act or activity for which a corporation may be organized under the General Corporation Law of the State of Delaware (the “DGCL”) and to possess and employ all powers and privileges now or hereafter granted or available under the laws of the State of Delaware to such corporations.

ARTICLE IV

A. The total number of shares of capital stock of all classes that the Corporation shall have authority to issue is 510,000,000 shares, consisting of: 500,000,000 shares of common stock, $0.0001 par value per share (“Common Stock”) and 10,000,000 shares of preferred stock, par value $0.0001 per share (“Preferred Stock”).

B. Except as otherwise restricted by this Amended and Restated Certificate of Incorporation (this “Certificate”), the Corporation is authorized to issue, from time to time, all or any portion of the capital stock of the Corporation which may have been authorized but not issued, to such person or persons and for such lawful consideration as it may deem appropriate, and generally in its absolute discretion to determine the terms and manner of any disposition of such authorized but unissued capital stock. Any and all such shares issued for which the full consideration has been paid or delivered shall be deemed fully paid shares of capital stock, and the holder of such shares shall not be liable for any further call or assessment or any other payment thereon.

C. The designations and the powers, preferences and rights and qualifications, limitations or restrictions of the shares of each class of stock are as follows:

1. Common Stock

(a) General. The voting, dividend and liquidation rights of the holders of the Common Stock are subject to the rights of the holders of any series of Preferred Stock then outstanding.

(b) Voting. Except as otherwise provided herein, the holders of the Common Stock are entitled to one (1) vote for each share of Common Stock held at all meetings of stockholders;

provided, however, that, except as otherwise required by law, holders of Common Stock, as such, shall not be entitled to vote on any amendment to this Certificate that relates solely to the terms of one or more outstanding series of Preferred Stock if the holders of such affected series are entitled, either separately or together with the holders of one or more other such series, to vote thereon pursuant to this Certificate or pursuant to the DGCL. There shall be no cumulative voting. The number of authorized shares of Common Stock may be increased or decreased (but not below the number of shares thereof then outstanding) by (in addition to any vote of the holders of one or more series of Preferred Stock that may be required, if any Preferred Stock is then outstanding) the affirmative vote of the holders of shares of capital stock of the Corporation representing a majority of all outstanding shares of capital stock of the Corporation entitled to vote, irrespective of the provisions of Section 242(b)(2) of the DGCL.

2. Preferred Stock. The shares of Preferred Stock shall initially be undesignated and may be issued from time to time in one or more additional series by the Board of Directors. The Board of Directors is hereby authorized, subject to any limitations prescribed by law, to determine or alter the rights, preferences, privileges and restrictions granted to or imposed upon a wholly-unissued series of Preferred Stock, and the number of shares constituting any such series and the designation thereof, or any of them; and to increase or decrease the number of shares constituting any such series and the designation thereof, or any of them; and to increase or decrease the number of shares of any series subsequent to the issue of shares of that series, but, in respect of decreases, not below the number of shares of such series then outstanding. In case the number of shares of any series should be so decreased, the shares constituting such decrease shall resume the status which they had prior to the adoption of the resolutions originally fixing the number of shares of such series. The number of authorized shares of Preferred Stock may be increased or decreased (but not below the number of shares thereof then outstanding) by the affirmative vote of the holders of a majority of the outstanding shares of Common Stock without a vote of the holders of the Preferred Stock, or of any series thereof, unless a vote of any such holders is required pursuant to the certificate or certificates establishing any series of Preferred Stock.

ARTICLE V

The Corporation is to have perpetual existence.

ARTICLE VI

The following provisions are inserted for the management of the business and the conduct of the affairs of the Corporation, and for further definition, limitation and regulation of the powers of the Corporation and of its directors and stockholders:

A. The business and affairs of the Corporation shall be managed by or under the direction of the Board of Directors. In addition to the powers and authority expressly conferred upon them by law or by this Certificate or the bylaws of the Corporation, as the same may be amended from time to time (the “Bylaws”), the directors are hereby empowered to exercise all such powers and do all such acts and things as may be exercised or done by the Corporation.

B. The directors of the Corporation need not be elected by written ballot unless the Bylaws so provide.

C. Subject to the rights of the holders of any series of Preferred Stock, 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.

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D. Subject to the rights of the holders of any series of Preferred Stock then outstanding, special meetings of stockholders of the Corporation may be called only by the Board of Directors pursuant to a resolution adopted by a majority of the total number of authorized directors (whether or not there exist any vacancies in previously authorized directorships at the time any such resolution is presented to the Board for adoption), the Chairperson of the Board or the Chief Executive Officer.

E. The number of directors shall be fixed from time to time exclusively by the Board of Directors pursuant to a resolution adopted by a majority of the total number of authorized directors (whether or not there exist any vacancies in previously authorized directorships at the time any such resolution is presented to the Board of Directors for adoption). Beginning immediately following the consummation of the Corporation’s initial public offering of its Common Stock pursuant to an effective registration statement under the Securities Act of 1933, as amended, (the “Initial Public Offering”), the directors shall, by resolution of the Board of Directors, be divided into three classes, hereby designated Class I, Class II and Class III. The term of office of the initial Class I directors shall expire at the first annual meeting of stockholders of the Corporation following the Initial Public Offering, the term of office of the initial Class II directors shall expire at the second annual meeting of stockholders of the Corporation following the Initial Public Offering, and the term of office of the initial Class III directors shall expire at the third annual meeting of stockholders of the Corporation following the Initial Public Offering. At each annual meeting of stockholders of the Corporation following the Initial Public Offering, directors elected to replace those of a Class whose terms expire at such annual meeting shall be elected for a term expiring at the third succeeding annual meeting of stockholders of the Corporation after such election. All directors shall hold office until the expiration of the term for which elected, and until their respective successors have been duly elected and qualified, except in the case of the death, resignation, or removal of any director. Nothing in this Certificate shall preclude a director from serving consecutive terms.

F. Subject to the rights of the holders of any series of Preferred Stock then outstanding, (i) newly created directorships resulting from any increase in the authorized number of directors and (ii) any vacancies in the Board of Directors resulting from death, resignation, disqualification, removal from office, or other cause may be filled only by the Board of Directors (and not by stockholders), provided that a quorum is then in office and present, or by a majority of the directors then in office, if less than a quorum is then in office, or by the sole remaining director. A director elected to fill a vacancy shall be elected for the unexpired term of such director’s predecessor in office and until such director’s successor is duly elected and qualified, or until such director’s earlier death, resignation, or removal. After the Initial Public Offering, a director chosen to fill a position resulting from an increase in the number of directors shall hold office until the next election of the class for which such director shall have been chosen, and until such director’s successor is duly elected and qualified, or until such director’s earlier death, resignation, or removal. No decrease in the authorized number of directors constituting the Board of Directors shall shorten the term of any incumbent director.

G. Subject to the rights of the holders of any series of Preferred Stock then outstanding, and notwithstanding any other provision of this Certificate, directors may be removed from office only for cause and only by the affirmative vote of the holders of at least sixty-six and two-thirds percent (66-2/3%) of the voting power of all of the then outstanding shares of the capital stock of the Corporation entitled to vote generally in the election of directors, voting together as a single class. Vacancies in the Board of Directors resulting from such removal shall be filled as set forth above under Article VI, Part F.

H. Subject to the rights of holders of any series of Preferred Stock, advance notice of stockholder nominations for election of directors and of business to be brought by stockholders before any meeting of stockholders of the Corporation shall be given in the manner provided by the Bylaws of the Corporation.

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ARTICLE VII

No director shall be personally liable to the Corporation or its stockholders for monetary damages for breach of such director’s fiduciary duty as a director of the Corporation, except for liability (i) for any breach of the director’s duty of loyalty to the Corporation or its stockholders, (ii) for any 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 hereafter is amended to authorize 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 herein, shall be limited to the fullest extent permitted by the amended DGCL. Any repeal or modification of this paragraph by the stockholders of the Corporation shall be prospective only and shall not adversely affect any limitation on the personal liability of a director of the Corporation existing at the time of such repeal or modification.

The Corporation shall indemnify any director or officer to the fullest extent permitted by Delaware law.

ARTICLE VIII

All of the powers of the Corporation, insofar as the same may be lawfully vested by this Certificate in the Board of Directors, are hereby conferred upon the Board of Directors.

ARTICLE IX

The Board of Directors is expressly empowered to adopt, amend or repeal the Bylaws. Any adoption, amendment or repeal of the Bylaws by the Board of Directors shall require the approval of a majority of the total number of authorized directors (whether or not there exist any vacancies in previously authorized directorships at the time any resolution providing for adoption, amendment or repeal is presented to the Board of Directors). The stockholders shall also have power to adopt, amend or repeal the Bylaws. Subject to the rights of the holders of any series of Preferred Stock then outstanding, any adoption, amendment or repeal of Bylaws by the stockholders shall require, in addition to any vote of the holders of any class or series of stock of the Corporation required by law or by this Certificate, the affirmative vote of the holders of at least sixty-six and two-thirds percent (66-2/3%) of the voting power of all of the then outstanding shares of the capital stock of the Corporation entitled to vote generally in the election of directors, voting together as a single class.

ARTICLE X

The Corporation reserves the right to amend or repeal any provision contained in this Certificate in the manner prescribed by the laws of the State of Delaware and all rights conferred upon stockholders are granted subject to this reservation; provided, that, notwithstanding any other provision of this Certificate or any provision of law which might otherwise permit a lesser vote or no vote, but subject to the rights of the holders of any series of Preferred Stock then outstanding and in addition to any vote of the holders of any class or series of the stock of this Corporation required by law or by this Certificate, the affirmative vote of the holders of at least sixty-six and two-thirds percent (66-2/3%) of the voting power of all of the then outstanding shares of the capital stock of the Corporation entitled to vote generally in the election of directors, voting together as a single class, shall be required to amend or repeal, or adopt any provision of this Certificate inconsistent with, Article VI, Article VII, Article VIII, this Article X or Article XII.

ARTICLE XI

If any provision of this Certificate becomes or is declared on any ground by a court of competent jurisdiction to be illegal, unenforceable or void, portions of such provision, or such provision in its entirety, to the extent necessary, shall be severed from this Certificate, and the court will replace such illegal, void or

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unenforceable provision of this Certificate with a valid and enforceable provision that most accurately reflects the Corporation’s intent, in order to achieve, to the maximum extent possible, the same economic, business and other purposes of the illegal, void or unenforceable provision. The balance of this Certificate shall be enforceable in accordance with its terms.

ARTICLE XII

Unless the Corporation consents in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware shall be the sole and exclusive forum for (a) any derivative action or proceeding brought on behalf of the Corporation, (b) any action asserting a claim of breach of a fiduciary duty owed by any director, officer, employee, agent or stockholder of the Corporation to the Corporation or the Corporation’s stockholders, (c) any action asserting a claim arising pursuant to any provision of the DGCL, this Certificate or the Bylaws or as to which the DGCL confers jurisdiction on the Court of Chancery of the State of Delaware or (d) any action asserting a claim governed by the internal affairs doctrine, in each such case subject to such Court of Chancery having personal jurisdiction over the indispensable parties named as defendants therein. In addition, unless the Corporation consents in writing to the selection of an alternative forum, the U.S. federal district courts shall, to the fullest extent permitted by law, be the sole and exclusive forum for the resolution of any complaint asserting a cause of action arising under the Securities Act of 1933, as amended. Notwithstanding anything herein to the contrary, this Article XII shall not apply to suits brought to enforce a duty or liability created by the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or the rules and regulations under the Exchange Act, or any other claim for which the U.S. federal courts have exclusive jurisdiction. To the fullest extent permitted by applicable law, any person or entity purchasing or otherwise acquiring or holding 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 XII.

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