The 2021 Idaho Vandals football team represented the University of Idaho in the Big Sky Conference during the 2021 NCAA Division I FCS football season. Led by ninth-year head coach Paul Petrino, the Vandals were 4–7 (3–5 in Big Sky, ninth), and played their home games on campus at the Kibbie Dome in Moscow, Idaho. After the season, Petrino was fired with a cumulative record of 34–66 (.340); the 66 losses were the most in program history, fifteen more than Skip Stahley (1954–61).