NORTHWEST PIPE CO

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

(Amendment No. ** ** ** )**

Filed by the Registrant ☒

Filed by a party other than the Registrant ☐

Check the appropriate box:

NORTHWEST PIPE COMPANY

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check all boxes that apply):

201 NE Park Plaza Drive, Suite 100

Vancouver, WA 98684

April 14, 2025

Dear Fellow Shareholder:

You are cordially invited to attend the 2025 Annual Meeting of Shareholders (the “Annual Meeting”) on Thursday, June 12, 2025, at 7:00 a.m. Pacific Time. As part of Northwest Pipe Company’s effort to encourage broader participation in the Annual Meeting, the Board of Directors has determined that the Annual Meeting will be conducted virtually via webcast instead of in-person. You will be able to attend the meeting, vote your shares, and submit questions by logging in atwww.virtualshareholdermeeting.com/NWPX2025.

As you review this Proxy, we want to draw your attention to a specific vote, Proposal #4. This is a pivotal moment for our Company, and we invite you, our valued shareholders, to vote yes on the proposed name change to NWPX Infrastructure, Inc. (“NWPX Infrastructure”). This rebranding marks the culmination of years of strategic growth, positioning us as a balanced and diversified water infrastructure leader. By embracing the NWPX Infrastructure name—aligned with our Nasdaq ticker symbol—we reinforce our confidence in the strength of our business, our commitment to innovation, and our focus on creating long-term shareholder value. Your vote is an investment in the strength and scalability of our evolving business, ensuring we remain at the forefront of the industry for years to come.

YOUR VOTE IS IMPORTANT. As a shareholder of Northwest Pipe Company, you can play an important role by considering and taking action on the matters set forth in the attached Proxy Statement. The time and attention you invest in making thoughtful decisions is appreciated.

It has been a rewarding year and, looking ahead, we are inspired by the tremendous opportunities for Northwest Pipe Company. On behalf of the Board, thank you for your investment in our Company.

Sincerely,

Scott Montross President and Chief Executive Officer

| Notice and Proxy Statement | 2025

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NOTICE OF ANNUAL MEETING OF SHAREHOLDERS

MEETING AGENDA

MEETING ADMISSION

The 2025 Annual Meeting of Shareholders (the “Annual Meeting”) of Northwest Pipe Company will be held via webcast on Thursday, June 12, 2025, at 7:00 a.m. Pacific Time atwww.virtualshareholdermeeting.com/NWPX2025. To participate in the Annual Meeting, you will need your unique 16‑digit control number printed in the box and marked by the arrow on your proxy card or on the voting instructions from your stockbroker, bank, or other nominee that accompanied your proxy materials. On the record date, there were 9,905,797 shares of Common Stock then outstanding, with each share of Common Stock being entitled to one vote.

VOTING PLATFORMS

Only shareholders of record at the close of business on April 10, 2025 are entitled to receive notice of, and to vote at, the Annual Meeting and any adjournments or postponements of the meeting. It is important that your shares be represented and voted at the meeting. Please complete, sign, and return your proxy card, or use the Internet or telephone voting systems.

IMPORTANT NOTICE REGARDING INTERNET AVAILABILITY OF PROXY MATERIALS

This Proxy Statement and the Company’s 2024 Annual Report to Shareholders for the Annual Meeting to be held on June 12, 2025 are also available atwww.proxyvote.com.

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FORWARD LOOKING STATEMENTS

Certain statements in this Proxy Statement, other than purely historical information, are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995 and Section 21E of the Securities Exchange Act of 1934, as amended (“Exchange Act”), that are based on current expectations, estimates, and projections about Northwest Pipe Company’s business, management’s beliefs, and assumptions made by management. Words such as “expects,” “anticipates,” “intends,” “plans,” “believes,” “seeks,” “estimates,” “forecasts,” “should,” “could,” and variations of such words and similar expressions are intended to identify such forward-looking statements. These statements are not guarantees of future performance and involve risks and uncertainties that are difficult to predict. Therefore, actual outcomes and results may differ materially from what is expressed or forecasted in such forward-looking statements as a result of a variety of important factors. Such forward-looking statements speak only as of the date on which they are made, and the Company does not undertake any obligation to update any forward-looking statement to reflect events or circumstances after the date of this Proxy Statement. If the Company does update or correct one or more forward-looking statements, investors and others should not conclude that it will make additional updates or corrections with respect thereto or with respect to other forward-looking statements.

| Notice and Proxy Statement | 2025

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