UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

SCHEDULE 14A

April 18, 202217, 2023

Dear Stockholder:

Details of the business to be conducted at the meeting are given in the Notice of Annual Meeting of Stockholders and Proxy Statement which follow this letter. The 20212022 Annual Report to Stockholders is also included with these materials.

We have mailed to many of our stockholders a Notice of Internet Availability of Proxy Materials (the “Notice”) containing instructions on how to access our 20222023 Proxy Statement and our 20212022 Annual Report to Stockholders, and how to vote online on the threefive management Proposals put before you this year. The Notice also includes instructions on how to request a paper or email copy of the proxy materials, including the Notice of Annual Meeting, Proxy Statement and Annual Report, and proxy card or voting instruction card. Stockholders who previously either requested paper copies of the proxy materials or elected to receive the proxy materials electronically did not receive a Notice and will receive the proxy materials in the format requested.

In addition, by following the e-consent instructions in the proxy card, stockholders may go paperless in future solicitations and request proxy materials electronically by email on an ongoing basis.

Your vote is important. Whether or not you plan to attend the Annual Meeting, we urge you to review the proxy materials and vote your shares, regardless of the number of shares you hold, as soon as possible. You may vote by proxy over the internet or by telephone using the instructions provided in the Notice. Alternatively, if you received paper copies of the proxy materials by mail, you can also vote by following the instructions on the proxy card or voting instruction card. Instructions regarding the three methods of voting are contained in the Notice, proxy card or voting instruction card.

If you have any questions about the meeting, please contact our Investor Relations Department at (203) 316-6537.

Sincerely,

By Order of the Board of Directors,

Stamford, Connecticut

April 18, 202217, 2023

TABLE OF CONTENTS

www.virtualshareholdermeeting.com/IT2022IT2023

For the Annual Meeting of Stockholders to be held on June 2, 20221, 2023

GENERAL INFORMATION

THE BOARD OF DIRECTORS

The matrix below summarizes what our Board believes are desirable types of experience, qualifications, attributes and skills possessed by one or more of Gartner’s directors because of their particular relevance to the Company’s business and structure. The following matrix does not encompass all the experience, qualifications, attributes or skills of our directors.

The Company has adopted a majority vote standard for the election of directors which provides that a nominee must receive more FOR votes than AGAINST votes for election as a director. Should a nominee fail to achieve this threshold, the nominee must immediately tender his or her resignation to the Board. The Governance/Nominating and Governance Committee (the “Governance Committee”) will then recommend to the Board whether to accept or reject the tendered resignation, and the Board, in its discretion, will

The Compensation Committee, in consultation with the Governance Committee, reviews all forms of independent director compensation and approves changes, when appropriate. The Compensation and Governance Committees are supported in this review by Exequity, LLP. The review examines director compensation in relation to two comparator groups: Peer Group and General Industry Reference Group. The Peer Group includes the same companies used to benchmark executive pay. The General Industry Reference Group includes 100 companies with median revenues similar to that of Gartner. Regular review of the director compensation program ensures that the director compensation is reasonable and reflects a mainstream approach to the structure of the compensation components and the method of delivery. Director compensation is primarily reviewed in relation to the Peer Group. Director compensation in 2021In January 2022, it was determined to approximatethat director compensation approximated the median of the Peer Group, and as such, no changes were made to director compensation. The section that follows describes the current director compensation program and components.for 2022.

Directors who are also employees receive no fees for their services as directors. Non-management directors are reimbursed for their meeting attendance expenses and receive the following compensation for their service as director:directors. The table below sets forth director compensation for 2022:

This table sets forth compensation earned or paid in cash, and the grant date fair value of equity awards made, to our non-management directors on account of services rendered as a director in 2021.2022. Mr. Hall receives no additional compensation for service as director. Mr. Gutiérrez was appointed to the Board in February of 2023 and did not receive any compensation from Gartner in 2022.

The Board believes directors should have a financial interest in the Company. Accordingly, each director is required to hold shares of Gartner common stock with a value of not less than five (5) times the Annual Director Retainer Fee ($60,000).Fee. Directors are required to achieve the guideline within three years of joining the Board. In the event a director has not satisfied the guideline within such three-year period, he/she will be required to hold 50% of net after-tax shares received from the Company either in the form of equity awards or released CSEs until the guideline is achieved. We permit directors to apply deferred and unvested equity awards towards satisfying these requirements. AsAll our directors as of December 31, 2021, all our directors2022 were in compliance with these guidelines.guidelines on that date.

CORPORATE GOVERNANCE

Gartner is committed to maintaining strong corporate governance practices.

Our Board Guidelines require that our Board be comprised of a majority of directors who meet the criteria for independence from management set forth by the New York Stock Exchange (the “NYSE”) in its corporate governance listing standards.

Our committee charters likewise require that our standing Audit, Compensation and Governance/NominatingGovernance Committees be comprised only of independent directors. Additionally, the Audit Committee members must be independent under Section 10A-3 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). The Compensation Committee members must be independent under Rule 16b-3 promulgated under the Exchange Act as well as applicable NYSE corporate governance listing standards, and they must qualify as outside directors under regulations promulgated under Section 162(m) (“Section 162(m)”) of the Internal Revenue Code of 1986, as amended (the “Code”).

Utilizing all of these criteria, as well as all relevant facts and circumstances, the Board annually assesses the independence from management of all non-management directors and committee members by reviewing the commercial, financial, familial, employment and other relationships between each director and the Company, its auditors and other companies that do business with Gartner. Because of our worldwide reach, it is not unusual for Gartner to engage in ordinary course of business transactions involving the sale of research or consulting services with entities affiliated with one of our directors, or their immediate family members. The Board considered these transactions in determining director independence and determined that such transactions did not impair any director’s independence.

After analysis and recommendation by the Governance Committee, the Board determined that:

The Board annually reviews its leadership structure to evaluate whether the structure remains appropriate. This flexibility allows the Board to review the structure of the Board and determine whether to separate the CEO and the Chairman based upon the Company’s needs and circumstances from time to time.

The Board of Directors is responsible for ensuring that an appropriate culture of risk management exists within Gartner. Our Board, together with management, oversees risk (including cybersecurity risk) at Gartner. The Board exercises its oversight both directly and through its committees. Each committee keeps the Board informed of its oversight efforts through regular reporting to the full Board by the committee chairpersons. The Company’s strategic objectives and activities are presented by executive management to the Board and approved annually and more frequently as necessary.

The General Counsel, who serves as Chief Compliance Officer, also reports directly to the Audit Committee on a quarterly basis concerning the effectiveness and status of the Company’s legal and ethical compliance program and initiatives, hotlinehelpline activities and litigation matters.

The Company maintains internal controls and procedures over financial reporting, as well as enterprise wide internal controls, which are updated and tested annually by management and our independent registered public accounting firm. Any internal control deficienciesOur independent registered public accounting firm also attends Audit Committee meetings, and the status of remediation efforts as well as any findings of the Disclosure Controls Committee are reported to the Audit Committee on a quarterly basis.meets with them in executive session quarterly.

COVID-19Data Privacy and Cybersecurity Risk Oversight

Risk Assessment of Compensation Policies and Practices

Our Board held fivefour meetings in 2021.2022. During 2021,2022, all our directors attended at least 75% of the Board and committee meetings held during the periods in which such director served as a director and/or committee member. At each regular quarterly Board and committee meeting, time is set aside for the non-management directors to meet in executive session without management present. Mr. James C. Smith, our non-executive Chairman of the Board, presides over the executive sessions at the Board meetings, and each committee chairperson presides over the executive sessions at their respective committee meetings. Directors are not required, but are invited, to attend the Annual Meeting of Stockholders. In 2021,2022, Mr. Hall and other executive officers of the Company attended the 20212022 Annual Meeting of Stockholders.

As noted above, our Board has three standing committees: Audit, Compensation and Governance/Nominating, and all committee members have been determined by our Board to be independent under applicable standards. Our Board has

approved a written charter for each standing committee, which is reviewed annually and revised as appropriate. The table below provides information for each Board committee in 2021:2022:

Gartner has a separately designated standing audit committee established in accordance with Section 3(a)(58)(A) of the Exchange Act. Our Board has determined that both Ms.Mses. Dykstra and Ferguson and Mr. Bressler qualify as audit committee financial experts, as defined by the rules of the Securities and Exchange Commission (the “SEC”), and that all members have the requisite accounting or related financial management expertise and are financially literate as required by the NYSE corporate governance listing standards.

The independent registered public accounting firm reports directly to the Audit Committee. By meeting with the independent registered public accounting firm, the internal auditor, and operating and financial management personnel, the Audit Committee oversees matters relating to accounting standards, policies and practices, any changes thereto and the effects of any changes on our financial statements, financial reporting practices and the quality and adequacy of internal controls. Additionally, our internal audit and compliance functions report directly to the Audit Committee. After each Audit Committee meeting, the Committee meets separately with the CFO, the Chief Compliance Officer, the internal auditor and the independent registered public accounting firm without management present.

Exequity, LLP (“Exequity”) was retained by the Compensation Committee to provide information, analyses and advice to the Committee during various stages of 20212022 executive compensation planning. Exequity reports directly to the Compensation Committee chair. In the course of conducting its activities, Exequity attended meetings of the Compensation Committee and briefed the Committee on executive compensation trends generally.

The Compensation Committee has assessed the independence of Exequity and has concluded that Exequity is independent and that its retention presents no conflicts of interest either to the Committee or the Company.

WhileThe Governance Committee is responsible for the Governance/Nominatingeffectiveness of the Board through its size and composition. The Board assesses its performance, effectiveness, composition, and appropriateness of the qualifications of existing directors, as part of the annual Board evaluation process. The annual evaluation is completed through a questionnaire process that is renewed annually to align with current regulations and best practices. The responses are collected by the General Counsel’s office and a summary of the results and comments are provided anonymously to the Governance Committee and full Board for review and consideration. This process promotes our commitment to continuous improvement and ensures our Board is effective.

ELECTION OF DIRECTORS

Our Board, acting throughon recommendation of the Governance Committee, is responsible for presenting for stockholder consideration each year a group of nominees that, taken together, has the experience, qualifications, attributes and skills appropriate and necessary to carry out the duties and responsibilities of, and to function effectively as, the board of directors of Gartner. The Governance Committee regularly reviews the composition of the Board in light of the needs of the Company, its assessment of board and committee performance, and the input of stockholders and other key stakeholders. The Governance Committee looks for certain common characteristics in all nominees, including integrity, strong professional experience and reputation, a record of achievement, constructive and collegial personal attributes and the ability and commitment to devote sufficient time and effort to board service. In addition, the Governance Committee seeks to include on the Board a complementary mix of individuals with diverse backgrounds and skills that will enable the Board as a whole to effectively manage the array of issues it will confront in furtherance of its duties. These individual qualities can include matters such as experience in the technology industry; experience managing and operating large public companies; international operating experience; financial, accounting, executive compensation and capital markets expertise; and leadership skills and experience.

EXECUTIVE OFFICERS

COMPENSATION DISCUSSION & ANALYSIS

This Compensation Discussion & Analysis, or “CD&A”, describes and explains the Company’s compensation philosophy and executive compensation program, as well as compensation awarded to and earned by, the following persons who were Named Executive Officers (“NEOs”) in 2021:2022:

The CD&A is organized into three sections:

The Board has resolved to present Say on Pay proposals to stockholders on an annual basis, respecting the sentiment of our stockholders as expressed in 2017. This year we are asking our stockholders once again to indicate their preference

for the frequency of Say on Pay proposals in Proposal Three (advisory vote on the frequency of Say on Pay proposals). As reflected by our Board’s recommendation in Proposal Three, the Company is committed to annual Say on Pay proposals. The Company and the Compensation Committee will consider the results of this year’s advisory Say on Pay proposal in future executive compensation planning activities. Over the past several years, stockholders have been consistent in their strong support of our executive compensation program. We also engage our stockholders from time to time to solicit their feedback on executive compensation and corporate governance matters. As such, no changes were made to the core structure of our compensation program as a result of the 20212022 Say on Pay vote.

This section explains the objectives of the Company’s compensation policies; what the compensation program is designed to reward; each element of compensation and why the Company chooses to pay each element; how the Company determines the amount (and, where applicable, the formula) for each element of pay; and how each compensation element and the Company’s decisions regarding that element fitsfit into the Company’s overall compensation objectives and affect decisions regarding other elements.

Our guiding philosophy is to provide a significant portion of executive compensation linked to corporate performance, thereby ensuring alignment and focus on Gartner’s performance. In addition, we believe that the design of the total compensation package must be competitive with the marketplace from which we hire our executive talent in order to achieve our objectives and attract and retain individuals who are critical to our long-term success. Our talent segment continues to be very competitive. We compete mainly with technology companies, which achieved record-breaking performance in 2021 and pose a significant threat to our ability to retain talent.

Our compensation program for executive officers is designed to compensate individuals for achieving and exceeding corporate performance objectives.objectives collectively. We believe this type of compensation encourages outstanding team performance (not simply individual performance), which builds stockholder value.

Both short-term and long-term incentive compensation is earned by executives only upon the achievement of certain measurable performance objectives that are deemed by the Compensation Committee and management to be critical to the Company’s short-term and long-term success. The amount of compensation ultimately earned will increase or decrease depending upon Company performance and the underlying price of our Common Stock (in the case of long-term equity-based incentive compensation).

To achieve the objectives noted above, our executive compensation program consists of three principal elements:

In General

The short-term and long-term incentive objectives provide executives with an opportunity to increase their total compensation package based upon the over-achievement of Company performance; similarly, in the case of under-achievement of Company performance, the value of incentive awards will fall below their target value, decreasing the total compensation opportunity. In addition, we assign a greater weighting to long-term awards than short-term awards in order to promote long-term decision-making to deliver top corporate performance, align management to stockholder interests and retain executives. We believe that long-term equity-based awards with vesting terms that are based on the achievement of pre-set financial targets and additional time-vesting serve as a strong retention incentive.

Determining Awards

Benchmarking and Peer Group

The Peer Group companies included:

Our Compensation Committee commissioned Exequity, its independent compensation consultant, to perform a competitive analysis of our executive compensation practices relative to the Peer Group, the primary reference, and secondarily to survey data. Exequity’s findings were considered by the Compensation Committee and by management in planning our 2021for 2022 executive compensation.compensation planning. The compensation study utilized market data from Aon’s Radford Global Technology Survey, Aon’sAon/Radford’s Total Compensation Measurement database, and Radford’s Broad High Technology Survey.database.

In addition, the Compensation Committee annually reviews an analysis conducted by Exequity that evaluates the connection between Gartner’s NEO pay and Company performance as measured by Total Shareholder Return and Shareholder Value. The analysis considers both 1-year and 3-year pay and performance for Gartner relative to the Peer Group. The findings indicated that pay realized by Gartner’s NEOs are aligned with Company performance.

Pay Mix