(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. UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 6-K REPORT OF FOREIGN ISSUER PURSUANT TO RULE 13a-16 OR 15d-1 ...

SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 20-F (Mark One) ☐ REGISTRATION STATEMENT PURSUANT TO SECTION 12(b) OR (g) OF THE SECURITIES EXCHANGE ACT OF 1934 OR ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to ☐ SHELL COMPANY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES E ...

Table of Contents SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 20-F (Mark One) ☐ REGISTRATION STATEMENT PURSUANT TO SECTION 12(b) OR (g) OF THE SECURITIES EXCHANGE ACT OF 1934 OR ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2019 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to ☐ SHELL COMPANY REPORT PURSUANT TO SECTION 13 OR 15(d) O ...

SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 20-F (Mark One) o REGISTRATION STATEMENT PURSUANT TO SECTION 12(b) OR (g) OF THE SECURITIES EXCHANGE ACT OF 1934 OR x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2018 OR Date of event requiring this shell company report . . . . . . . . . . . . . . . . . . . Commission file number 001-35193 GRIFOLS, S.A. (Exact name of Registrant as specified in its charter) (Address ...