1921 Copa del Rey
|Goals scored||50 (4.17 per match)|
The competition started on April 9, 1921, and concluded on May 8, 1921, with the Final, held at the San Mamés in Bilbao, in which Athletic Bilbao lifted the trophy for the 8th time ever with a 4–1 victory over Athletic Madrid.
- Biscay: Athletic de Bilbao
- Gipuzkoa: Real Unión
- Center Region: Athletic Madrid
- South Region: Sevilla FC
- Galicia: Fortuna Vigo
- Asturias: Sporting de Gijón
- Catalonia: FC Barcelona
- Levante: SR Levante
FC Barcelona withdrew in protest of the decision of Spanish Federation of moving the site of final from Seville to Bilbao. Athletic Madrid, his opponent, qualified for the semifinals.
April 3, 1921
|Athletic Bilbao||2–1||Sporting Gijón|
Fortuna Vigo and Real Unión won one match each. At that year, the goal difference was not taken into account. A replay match was played.
Athletic Bilbao qualified for the semifinals.
Sevilla FC qualified for the semifinals.
Real Unión qualified for the semifinals.
Athletic Madrid qualified for the final.
Sevilla FC won the semifinals, but was disqualified because of illegal line up in quarter finals. Athletic Bilbao qualified for the final.
May 8, 1921
|Athletic Bilbao||4–1||Athletic Madrid|
| Laca 29', 73'
Acedo 41' (pen.), 68'
|Copa del Rey 1921 winners|