AT&T INC.

This Proxy Statement is furnished in connection with the solicitation of proxies by the Board of Directors of AT&T Inc. (AT&T, the Company, or we) for use at the 2024 Annual Meeting of Stockholders of AT&T. The meeting will be conducted virtually over the Internet at 3:30 p.m. Central time on Thursday, May 16, 2024.

The purpose of the meeting is set forth in the Notice of Annual Meeting of Stockholders. This Proxy Statement and form of proxy are being sent or made available beginning April 4, 2024, to stockholders who were record holders of AT&T’s common stock, $1.00 par value per share, at the close of business on March 18, 2024. These materials are also available at www.envisionreports.com/att. Each share entitles the registered holder to one vote. As of March 18, 2024, there were 7,173,434,903 shares of AT&T common stock entitled to vote at the meeting.

To constitute a quorum to conduct business at the meeting, stockholders representing at least 40% of the shares of common stock entitled to vote at the meeting must be present or represented by proxy.

Each share of AT&T common stock represented at the Annual Meeting is entitled to one vote on each matter properly brought before the meeting. All matters, except as provided below, are determined by a majority of the votes cast, unless a greater number is required by law or our Certificate of Incorporation for the action proposed. A majority of votes cast means the number of votes cast “for” a matter exceeds the number of votes cast “against” such matter.

If the proxy is submitted and no voting instructions are provided, the person or persons designated on the card will vote the shares for the election of the Board of Directors’ nominees and in accordance with the recommendations of the Board of Directors on the other subjects listed on the proxy card and at their discretion on any other matter that may properly come before the meeting.

The Board of Directors is not aware of any matters that will be presented at the meeting for action on the part of stockholders other than those described in this Proxy Statement.

Election of Directors

In the election of Directors, each Director is elected by the vote of the majority of the votes cast with respect to that Director’s election. Under our Bylaws, if a

nominee for Director is not elected and the nominee is an existing Director standing forre-election (or incumbent Director), the Director must promptly tender his or her resignation to the Board, subject to the Board’s acceptance. The Governance and Policy Committee will make a recommendation to the Board as to whether to accept or reject the tendered resignation or whether other action should be taken. The Board will act on the tendered resignation, taking into account the Governance and Policy Committee’s recommendation, and publicly disclose (by a press release, a filing with the SEC, or other broadly disseminated means of communication) its decision regarding the tendered resignation and the rationale behind the decision within 90 days from the date of the certification of the election results. The Governance and Policy Committee in making its recommendation and the Board of Directors in making its decision may each consider any factors or other information that they consider appropriate and relevant. Any Director who tenders his or her resignation as described above will not participate in the recommendation of the Governance and Policy Committee or the decision of the Board of Directors with respect to his or her resignation.

If the number of persons nominated for election as Directors as of ten days before the record date for determining stockholders entitled to notice of or to vote at such meeting shall exceed the number of Directors to be elected, then the Directors shall be elected by a plurality of the votes cast. Because no persons other than the incumbent Directors have been nominated for election at the 2024 Annual Meeting, the majority vote provisions will apply.

Advisory Vote on Executive Compensation

The advisory vote on executive compensation isnon-binding, and the preference of the stockholders will be determined by the choice receiving the greatest number of votes.

All Other Matters to be Voted Upon

All other matters at the 2024 Annual Meeting will be determined by a majority of the votes cast.

Abstentions

Except as noted above, shares represented by proxies marked “abstain” with respect to the proposals described on the proxy card and by proxies marked to deny discretionary authority on other matters will not be counted in determining the vote obtained on such matters.

GENERAL

Broker Non-Votes

Under the rules of the New York Stock Exchange (“NYSE”), on certain routine matters, brokers may, at their discretion, vote shares they hold in “street name” on behalf of beneficial owners who have not returned voting instructions to the brokers. On all other matters, brokers are prohibited from voting uninstructed shares. In instances where brokers are prohibited from exercising discretionary authority(so-called brokernon-votes), the shares they hold are not included in the vote totals.

At the 2024 Annual Meeting, brokers will be prohibited from exercising discretionary authority with respect to each of the matters submitted other than the ratification of the auditors. As a result, for each of the matters upon which the brokers are prohibited from voting, the brokernon-votes will have no effect on the results.

VOTING

Stockholders of Record

Stockholders whose shares are registered in their name on the Company records (also known as “stockholders of record”) will receive either a proxy card by which they may indicate their voting instructions or a notice on how they may obtain a proxy. Instead of submitting a signed proxy card, stockholders may submit their proxies by telephone or through the Internet. Telephone and Internet proxies must be used in conjunction with, and will be subject to, the information and terms contained on the form of proxy. Similar procedures may also be available to stockholders who hold their shares through a broker, nominee, fiduciary or other custodian.

All shares represented by proxies will be voted by one or more of the persons designated on the form of proxy in accordance with the stockholders’ directions. If the proxy card is signed and returned or the proxy is submitted by telephone or through the Internet without specific directions with respect to the matters to be acted upon, it will be treated as an instruction to vote such shares in accordance with the recommendations of the Board of Directors. Any stockholder giving a proxy may revoke it at any time before the proxy is voted at the meeting by giving written notice of revocation to the Secretary of AT&T, by submitting a later-dated proxy, or by virtually

attending the meeting and voting electronically. The Chairman of the Board will announce the closing of the polls during the Annual Meeting. Proxies must be received before the closing of the polls in order to be counted.

Shares Held Through a Broker, Nominee, Fiduciary, or Other Custodian

Where the stockholder is not the record holder (“Beneficial Stockholder”), such as where the shares are held through a broker, nominee, fiduciary or other custodian, the stockholder must provide voting instructions to the record holder of the shares in accordance with the record holder’s requirements in order to ensure the shares are properly voted. Beneficial Stockholders that attend the virtual meeting will be able to vote, change a prior vote, or ask questions.

Shares Held on Your Behalf under Company Benefit Plans or under The DirectSERVICE Investment Program

The proxy card, or a proxy submitted by telephone or through the Internet, will also serve as voting instructions to the plan administrator or trustee for any shares held on behalf of a participant under any of the following employee benefit plans: the AT&T Retirement Savings Plan; the AT&T Savings and Security Plan; the AT&T Puerto Rico Retirement Savings Plan; and the BellSouth Savings and Security Plan. Subject to the trustee’s fiduciary obligations, shares in each of the above employee benefit plans for which instructions are not received will not be voted. To allow sufficient time for voting by the trustees and/or administrators of the plans, your voting instructions must be received by May 13, 2024.

In addition, the proxy card or a proxy submitted by telephone or through the Internet will constitute voting instructions to the plan administrator under The DirectSERVICE Investment Program sponsored and administered by Computershare Trust Company, N.A. (AT&T’s transfer agent) for shares held on behalf of plan participants.

If a stockholder participates in the plans listed above and/or maintains stockholder accounts under more than one name (including minor differences in registration, such as with or without a middle initial), the stockholder may receive more than one set of proxy materials. To ensure that all shares are voted, please submit proxies for all of the shares you own.