Avantor, Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

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AVANTOR, INC.

(Name of Registrant as Specified In Its Charter)

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MESSAGE FROM

OUR CHAIRMAN

We are pleased to invite stockholders to learn more about Avantor's recent progress. We appreciate your vote on related materials in our Proxy Statement at our 2025 Annual Meeting of Stockholders on May 8, 2025, at 11:00 a.m. Eastern Time.

Today, the Company has established itself as a leading global partner for laboratory consumables, bioprocessing materials and medical grade silicone formulations. More than 60% of Avantor's end-market business is in biopharma and healthcare. We support 300,000 labs in 180 countries around the world and Avantor chemicals and materials are currently specified into 85% of thetop 20 commercialized biologics.

2024 was a year of important progress across the enterprise. Avantor implemented a new operating model based around two global segments - laboratory solutions and bioscience production - while transforming its cost structure. The new operating model sharpens Avantor's focus on customers' laboratory and production needs, unlocks additional efficiencies and better positions Avantor for long-term growth. These changes are already delivering results. The Company executed on its cost savings initiatives ahead of schedule in 2024 and delivered free cash flow conversion of over 110%. The investments we continue to make in our business build Avantor’s capabilities and competitive differentiators, so the Company is well positioned to capitalize on improving market trends.

This is truly the golden age of science, and Avantor is proud to be an integral part of the breakthrough therapies that are changing lives for patients.

I am proud to lead the Avantor Board of Directors, a group of professionals with extensive experience across life sciences, finance and healthcare. To further bolster the Board's role in driving innovation at Avantor, in 2024 we created a Science and Technology Committee, responsible for overseeing the company's research and development strategies, plans and goals as well as identifying emerging science and technology trends. We also added to the depth and breadth of our Board with the addition of Dame Louise Makin. Dame Louise brings deep operating and M&A experience to the team.

The Board and management team are committed to delivering sustainable value to our customers and stockholders by driving science forward for the benefit of patients.

We value our continued dialogue with our stockholders and consider the feedback we receive as an important input to our decision-making process.

On behalf of our Board, our management team and our thousands of associates around the world, thank you for your support and for your investment in Avantor.

Jonathan Peacock

Chairman

Notice of 2025 Annual Meeting of Stockholders

VIRTUAL STOCKHOLDERS MEETING

The Annual Meeting of Stockholders (“Annual Meeting”) of Avantor, Inc. (“Avantor” or the “Company”) will be held on Thursday, May 8, 2025 at 11:00 a.m. Eastern Time. This year’s Annual Meeting will be a completely “virtual meeting,” conducted via live audio webcast on the Internet. Stockholders will be able to listen to and participate in the meeting online, vote their shares electronically and submit questions during the meeting by visiting www.virtualshareholdermeeting.com/AVTR2025. Participants will need the 16-digit control number included on their Notice of Internet Availability or proxy card to gain access to the meeting. Stockholders of record of Avantor common stock at the close of business on March 14, 2025 will be able to vote online during the meeting. You have received these proxy materials because our Board of Directors is soliciting your proxy to vote your shares at the 2025 Annual Meeting of Stockholders.

The purposes of the meeting are:

to elect the ten directors named in this Proxy Statement to serve a one-year term expiring at the 2026 annual meeting of stockholders;

to ratify the appointment of Deloitte & Touche LLP as the Company’s independent registered public accounting firm for 2025;

to approve, on an advisory basis, named executive officer compensation; and

to transact such other business as may properly come before the meeting or any adjournment or postponement thereof.

Your vote is important. We encourage you to vote by proxy in advance of the Annual Meeting. Whether or not you plan to attend via live audio webcast, we hope you will vote as soon as possible. Your proxy materials include instructions on how to vote, including by Internet. If you hold your shares through a brokerage firm, bank, or other similar entity, please follow their instructions. For more information on how to attend the meeting and vote, see "Questions and Answers About the Meeting and Voting" in the Proxy Statement.

On behalf of Avantor’s Board of Directors,

Claudius O. Sokenu

Executive Vice President, Chief Legal and Compliance Officer and Corporate Secretary

This Notice of 2025 Annual Meeting and Proxy Statement, together with our Annual Report on Form 10-K for the fiscal year ended December 31, 2024, were first made available to stockholders on or about March 28, 2025.

Important Notice Regarding the Availability of Proxy Materials for the Stockholder Meeting to Be Held on May 8, 2025: This Notice and Proxy Statement and our Annual Report are available free of charge at www.proxyvote.com, a site that does not have “cookies” that identify visitors to the site.

Table of Contents

Forward-Looking and Cautionary StatementsCertain of the statements contained in this Proxy Statement are forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the "Securities Act") and Section 21E of the Securities Exchange Act of 1934, as amended (the "Exchange Act") and are subject to the safe harbor created thereby under the Private Securities Litigation Reform Act of 1995. Forward-looking statements discuss our current expectations and projections relating to our financial condition, results of operations, plans, objectives, future performance and business. These statements may be preceded by, followed by or include the words “aim,” “anticipate,” “assumption,” “believe,” “continue,” “estimate,” “expect,” “forecast,” “goal,” “guidance,” “intend,” “likely,” “long-term,” “near-term,” “objective,” “opportunity,” “outlook,” “plan,” “potential,” “project,” “projection,” “prospects,” “seek,” “target,” “trend,” “can,” “could,” “may,” “should,” “would,” “will,” the negatives thereof and other words and terms of similar meaning. We have based these forward-looking statements on our current expectations and projections about future events. Although we believe that our assumptions made in connection with the forward-looking statements are reasonable, we cannot assure you that the assumptions and expectations will prove to be correct. Factors that could contribute to these risks, uncertainties and assumptions include, but are not limited to, the factors described in “Risk Factors” in our most recent Annual Report on Form 10-K, as such risk factors may be updated from time to time in our periodic filings with the SEC. All forward-looking statements speak only as of the date of this Proxy Statement. We undertake no obligations to update or revise publicly any forward-looking statements, whether as a result of new information, future events or otherwise other than as required under the federal securities laws.