Company: GLPG
Filing Date: 2025-07-24
Form Type: 6-K
Source: 0001193125-25-163796
Chunk: 0

Company: GALAPAGOS NV
Filing Date: 2025-07-24
Form: 6-K
Chunk 0
---
### UNITED STATES

### SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

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

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of July 2025

Commission File Number: 001-37384

### GALAPAGOS NV
(Translation of registrant’s name into English)

Generaal De Wittelaan L11 A3, 2800 Mechelen, 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 ☒ Form 40-F ☐

First Half-Year 2025 Results On July 23, 2025, the Registrant announced its unaudited first half-year results for 2025 in a press release and half year-report, copies of which are attached hereto as Exhibits 99.1 and 99.2, respectively, and are incorporated herein by reference.

The information contained in this Report on Form 6-K,including Exhibits 99.1 and 99.2, except for the quotes of Mr. Henry Gosebruch and Mr. Aaron Cox included in Exhibit 99.1, is hereby incorporated by reference into the Company’s Registration Statements on Form S-8(File Nos. 333-204567, 333-208697, 333-211834, 333-215783, 333-218160, 333-225263, 333-231765, 333-249416, 333-260500, 333-268756, 333-275886,and 333-283361).

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.

| Date: July 24, 2025 |     | GALAPAGOS NV          
 (Registrant)          
 /s/ Annelies Denecker |
|:--------------------|:----|:----------------------|
|                     |     | Annelies Denecker     |
|                     |     | Company Secretary     |