| Competition: | Uruguayan Primera División |
| Season: | 1921 (21st) |
| Winners: | Peñarol |
| Relegated: | Reformers |
| Matches: | 132 |
| Total Goals: | 300 |
| Prevseason: | 1920 |
| Nextseason: | 1922 |
The Uruguayan Championship 1921 was the 21st season of Uruguay's top-flight football league.
The tournament consisted of a two-wheel championship of all against all. It involved twelve teams, and the champion was Peñarol.
| Team | City | Stadium | Capacity | Foundation | Seasons | Consecutive seasons | Titles | 1920 | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Belgrano | Montevideo | 2 | 2 | align=center | - | 9th | ||||||
| Central | Montevideo | 5 January 1905 | 12 | 12 | align=center | - | 3rd | |||||
| Charley | Montevideo | 4 | 4 | align=center | - | 11th | ||||||
| Dublin | Montevideo | 10 | 5 | align=center | - | 10th | ||||||
| Lito | Montevideo | 1917 | align=center | - | align=center | - | align=center | - | align=center | - | ||
| Liverpool | Montevideo | 15 February 1915 | 1 | 1 | align=center | - | 8th | |||||
| Nacional | Montevideo | Gran Parque Central | 15,000 | 14 May 1899 | 19 | 19 | 8 | 1st | ||||
| Peñarol / CURCC | Montevideo | 28 September 1891 | 20 | 20 | 6 | 2nd | ||||||
| Reformers | Montevideo | 8 | 8 | align=center | - | 6th | ||||||
| Universal | Montevideo | 9 | 9 | align=center | - | 4th | ||||||
| Uruguay Onward | Montevideo | 1 | 1 | align=center | - | 7th | ||||||
| Montevideo Wanderers | Montevideo | 15 August 1902 | 17 | 17 | 2 | 5th |