Western Canada Rugby Football Union joined the CRU and challenged for the Grey Cup. The Edmonton Eskimos became the first Western team to play in a Grey Cup game, but lost to the Toronto Argonauts 23–0.
Rule changes included reducing players from 14 to 12 per side; putting ball into play by snapping it back; limit of 18 players with substitutes permitted freely.
Regular season
Final regular season standings
Note: GP = Games Played, W = Wins, L = Losses, T = Ties, PF = Points For, PA = Points Against, Pts = Points
*Bold text means that they have clinched the playoffs
Manitoba Rugby Football Union
| Team | GP | W | L | T | PF | PA | Pts |
|---|
| Winnipeg Victorias | 4 | 4 | 0 | 0 | 59 | 37 | 8 |
| Winnipeg Tammany Tigers | 4 | 2 | 2 | 0 | 53 | 41 | 4 |
| University of Manitoba Varsity | 4 | 0 | 4 | 0 | 53 | 87 | 0 |
|
Saskatchewan Rugby Football Union
| Team | GP | W | L | T | PF | PA | Pts |
|---|
| Southern Saskatchewan |
| Regina Rugby Club | 4 | 4 | 0 | 0 | 86 | 11 | 8 |
| Regina Boat Club | 4 | 2 | 2 | 0 | 34 | 28 | 4 |
| Moose Jaw | 4 | 0 | 4 | 0 | 12 | 93 | 0 |
| Northern Saskatchewan |
| Saskatoon Quakers | 3 | 2 | 1 | 0 | 43 | 18 | 4 |
| University of Saskatchewan Varsity | 3 | 1 | 2 | 0 | 18 | 43 | 2 |
Alberta Rugby Football Union
| Team | GP | W | L | T | PF | PA | Pts |
|---|
| Edmonton Eskimos | 3 | 3 | 0 | 0 | 148 | 5 | 6 |
| University of Alberta Varsity | 4 | 1 | 3 | 0 | 35 | 113 | 2 |
| Calgary Rugby Club | 3 | 1 | 2 | 0 | 39 | 104 | 2 |
* Final game of the season was cancelled - not necessary
Grey Cup Playoffs
Note: All dates in 1921
SRFU Playoff
| Date | Away | Home |
|---|
| November 4 | Regina Rugby Club 6 | Saskatoon 9 |
- Regina won the game played on October 29. After a successful protest, the game was replayed on November 4.
- Saskatoon advances to the WCRFU Semi-Final
Eastern Semi-Final
- Toronto Argonauts advance to the Eastern Final.[3]
Eastern Final
- Toronto Argonauts advance to the Grey Cup.
Western Semi-Final
| Date | Away | Home |
|---|
| November 7 | Saskatoon Quakers 1 | Winnipeg Victorias 16 |
[4]
Western Final
- Edmonton advances to the Grey Cup
Playoff Bracket
| Quarter Finals
| | | Semi Finals
| | | Grey Cup Final
| |
| | | | | | | | | | | | | | |
| | |
| ORFU
| Toronto Parkdale
|
| |
|
|
| BYE
|
| |
| | ORFU
| Toronto Parkdale
| 8
| |
| EAST
|
| | IRFU
| Toronto Argonauts
| 16
| |
| IRFU
| Toronto Argonauts
| 20
| |
| |
| CIRFU
| University of Toronto
| 12
| |
| | IRFU
| Toronto Argonauts
| 23
| |
|
|
| | ARFU
| Edmonton Eskimos
| 0
| |
| ARFU
| Edmonton Eskimos
|
| | |
| |
|
| BYE
|
| |
| | ARFU
| Edmonton Eskimos
| 16
| |
| WEST
|
| | MRFU
| Winnipeg Victorias
| 6
| |
| MRFU
| Winnipeg Victorias
| 16
| |
| |
| SRFU
| Saskatoon Quakers
| 1
| |
|
|
NOTE: During this time most players played both ways, so the All-Star selections do not distinguish between some offensive and defensive positions.
- FW - Warren Synder, University of Toronto
- HB - Harry Batstone, Toronto Argonauts
- HB - Joe Breen, Toronto Parkdale
- HB - Lionel Conacher, Toronto Argonauts
- QB - Johnny Evans, Queen's University
- QB - Hugh Cochrane, Toronto Argonauts
- C - Lionel Shoebottom, Toronto Parkdale
- C - ???, Toronto Argonauts
- G - R. McCombe, McGill University
- G - Harold Pugh, Toronto Argonauts
- G - ???, Hamilton Tigers
- T - Doug Ambridge, McGill University
- T - John McKelvey, Queen's University
- T - Alex Romeril, Toronto Argonauts
- E - Ernie Rolph, University of Toronto
- E - Bud Thomas, Ottawa Rough Riders