6-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of November 2025

Commission File Number: 001-36515

Materialise NV

Technologielaan 15

3001 Leuven

Belgium

(Address of principal executive office)

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

Form 20-F  x            Form 40-F  ¨

This Form 6-K (other than Exhibit 99.1 hereto) is incorporated by reference into the registrant’s Registration Statement on Form F-3 (File No. 333-213649).

On November 14, 2025, Materialise NV (the “Company” or “Materialise”) announced the results of its previously announced extraordinary meeting of its shareholders (the “Special Meeting”), held on November 14, 2025.

At the Special Meeting, resolutions were passed: (i) to, among other things, proceed with certain share capital movements (and related amendments to the articles of association) with a view to the Company’s previously announced potential buyback program, (ii) to grant the board of directors a new authorization for buybacks (and a related amendment to the articles of association), (iii) to make certain other amendments to the articles of association (including the introduction of double voting rights for certain shares) and adopt a new text of the articles of association, (iv) to approve the remuneration policy, (v) to mandate the statutory auditor with the assurance of sustainability information, and (vi) to confirm the composition of the board of directors and the qualification of each director as independent, non-executive and/or executive. The new articles of association will become effective upon the listing of the Company’s ordinary shares on Euronext Brussels.

Attached as Exhibit 99.1 hereto is a copy of the Company’s press release announcing the Special Meeting results.

EXHIBIT INDEX

SIGNATURE

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.

Date: November 14, 2025

Exhibit 99.1

Materialise NV Announces Results of 2025 ExtraordinaryShareholders’ Meeting

November 14, 2025

Leuven, Belgium – November 14, 2025 — Materialise NV (NASDAQ: MTLS), a leading provider of additive manufacturing software and of sophisticated 3D printing solutions, today announced the results of the votes cast at its Extraordinary Shareholders’ Meeting, where all the proposed resolutions were approved.

For additional information, please visit: https://investors.materialise.com/

About Materialise NV

Materialise NV incorporates more than three decades of 3D printing experience into a range of software solutions and 3D printing services that empower sustainable 3D printing applications. Our open, secure, and flexible end-to-end solutions enable flexible industrial manufacturing and mass personalization in various industries — including healthcare, automotive, aerospace, eyewear, art and design, wearables, and consumer goods. Headquartered in Belgium and with branches worldwide, Materialise NV combines the largest group of software developers in the industry with one of the world's largest and most complete 3D printing facilities.

For additional information, please visit: www.materialise.com

Kristof Sehmke

Materialise NV

kristof.sehmke@materialise.be