Company: BCDRF
Filing Date: 2025-04-28
Form Type: 6-K
Source: 0000950103-25-005270
Chunk: 0

Company: Banco Santander, S.A.
Filing Date: 2025-04-28
Form: 6-K
Chunk 0
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<div align='center'>FORM 6-K

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Report of Foreign Issuer

Pursuant to Rule 13a-16 or 15d-16 of

the Securities Exchange Act of 1934

For the month of April, 2025

Commission File Number: 001-12518

Banco Santander, S.A.

(Exact name of registrant as specified in its charter)

Ciudad Grupo Santander

28660 Boadilla del Monte (Madrid) Spain

(Address of principal executive office)</div>

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 |

<div align='center'>Banco Santander, S.A.

TABLE OF CONTENTS</div>

Item 1

Banco Santander, S.A.(“Banco Santander”or the “Bank”), in compliance with the Securities Market legislation, hereby communicates the following:

<div align='center'>OTHER RELEVANT INFORMATION</div>

| Banco Santander notes the recent speculation                                                                                                
 regarding a potential transaction involving Santander Bank Polska, S.A. (“Santander Polska”) and confirms that it has received              
 interest from several parties and is currently in discussions with Erste Group Bank AG for the potential sale of a 49% stake in Santander   
 Polska. There is no certainty that the discussions will lead to an agreement being reached and, in any event, completion of any transaction 
 would be subject to closing conditions. A further announcement would be made if required.                                                   
 Boadilla del Monte (Madrid), 28 April                                                                                                       
 2025                                                                                                                                        |

<div align='center'>SIGNATURE</div>

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: | April 28, 2025 |     | Banco Santander, S.A. 
 By:                   | /s/ Pedro de Mingo Kaminouchi |                              |
|:------|:---------------|:----|:----------------------|:------------------------------|:-----------------------------|
|       |                |     |                       | Name:                         | Pedro de Mingo Kaminouchi    |
|