| Year: | 1921 |
| Team: | Idaho Vandals |
| Sport: | football |
| Conference: | Northwest Conference |
| Short Conf: | Northwest |
| Record: | 4–3–1 |
| Conf Record: | 1–2–1 |
| Head Coach: | Thomas Kelley |
| Hc Year: | 2nd |
| Stadium: | MacLean Field |
The 1921 Idaho Vandals football team represented the University of Idaho as a member of the Northwest Conference during the 1921 college football season. Led by Thomas Kelley in his second and final season as head coach, the Vandals compiled an overall record of 4–3–1 with a mark of 1–2–1 in conference play, placing fifth in the Northwest Conference.[1] [2] The Vandals had two home games in Moscow, one on campus at MacLean Field and another at the fairgrounds; they also played one in Boise at Public School Field.[3]
The following June, Kelley left for the University of Missouri and was succeeded at Idaho by Robert L. Mathews.[4] [5]