UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 6-K

Report of Foreign Issuer Pursuant to Rule 13a-16 or 15d-16

of the Securities Exchange Act of 1934

For the month of May 2026

Commission File Number: 001-02413

Canadian National Railway Company

(Translation of registrant’s name into English)

935 de la Gauchetiere Street West

Montreal, Quebec

Canada H3B 2M9

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

CANADIAN NATIONAL RAILWAY COMPANY

Table of Content

VIA SEDAR

May 1, 2026

Alberta Securities Commission

British Columbia Securities Commission

Manitoba Securities Commission

Financial and Consumer Services Commission (New Brunswick)

Office of the Superintendent of Securities Service Newfoundland and Labrador

Office of the Superintendent of Securities (Northwest Territories)

Nova Scotia Securities Commission

Ontario Securities Commission

Financial and Consumer Services Division (Prince Edward Island)

Financial and Consumer Affairs Authority of Saskatchewan

Office of the Yukon Superintendent of Securities

Office of the Superintendent of Securities Nunavut

Following the Annual Meeting of Shareholders of Canadian National Railway Company (the “Company”) held on Friday, May 1, 2026, at 10:00 a.m. (Eastern Daylight Time) via live webcast (the “Meeting”), and in accordance with section 11.3 of NI 51-102, we hereby advise you of the following voting results obtained at the Meeting.

A ballot was conducted with respect to the election of directors. The 11 director nominees proposed by management were elected as directors. According to proxies received and ballots cast, each of the following 11 individuals were elected as directors of the Company until the next annual shareholder meeting or until such person’s successor is elected or appointed, with the following results:

KPMG LLP was appointed as the Company’s auditors until the next annual meeting of shareholders by a majority of the shareholders on vote by ballot. The percentage of common shares voted “FOR” the appointment of the auditors was 89.69% of the common shares represented at the Meeting, as follows:

Votes FOR —420,948,358 (89.69%)

Votes WITHHELD — 48,389,841 (10.31%)

A ballot was conducted with respect to the non-binding advisory vote on the Company’s approach to executive compensation. The percentage of common shares voted “FOR” the Company’s approach to executive compensation was 91.67% of the common shares represented at the Meeting, as follows:

Votes FOR — 418,898,845 (91.67%)

Votes AGAINST — 38,049,816 (8.33%)

A ballot was conducted with respect to the non-binding advisory vote on the Company’s Climate Action Plan. The percentage of common shares voted “FOR” the Company’s Climate Action Plan was 95.99% of the common shares represented at the Meeting, as follows:

Votes FOR — 438,622,776 (95.99%)

Votes AGAINST — 18,326,303 (4.01%)