6-K

UNITED STATESSECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN ISSUERPURSUANT TO RULE 13a-16 OR 15d-16 OF THESECURITIES EXCHANGE ACT OF 1934

For the month September 2021

(Commission File No. 001-35193)

Grifols, S.A.

(Translation of registrant’s name into English)

Avinguda de la Generalitat, 152-158

Parc de Negocis Can Sant Joan

Sant Cugat del Valles 08174

Barcelona, Spain

(Address of registrant’s principal executive office)

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

Form 20-F  x  Form 40-F ¨

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101 (b) (1):

Yes ¨  No x

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101 (b) (7):

Yes ¨  No x

Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

Yes ¨  No x

If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): 82-         .                       .

Grifols, S.A.

TABLE OF CONTENTS

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, thereto duly authorized.

Date:  September 17, 2021