| Year: | 1921 |
| Team: | Idaho Vandals |
| Sport: | football |
| Conference: | Independent |
| Record: | 4–3–1 |
| Head Coach: | Thomas Kelley |
| Hc Year: | 2nd |
| Stadium: | MacLean Field |
The 1921 Idaho Vandals football team represented the University of Idaho in the 1921 college football season. Idaho was led by second-year head coach Thomas Kelley in their last season as an independent before joining the Pacific Coast Conference.[1] [2] The Vandals had two home games in Moscow, one on campus at MacLean Field and another at the fairgrounds;[3] they also played one in Boise at Public School Field.
Idaho dropped a seventh consecutive game to Washington State in the Battle of the Palouse, falling at Rogers Field Two years later, the Vandals won the first of three consecutive, their only three-peat in the rivalry series.
The following June, Kelley left for the University of Missouri.[2] [4] and was succeeded at Idaho in 1922 by Robert "Matty" Mathews.