The 2021 Old Dominion Monarchs football team represented Old Dominion University during the 2021 NCAA Division I FBS football season. The Monarchs played their home games at S.B. Ballard Stadium in Norfolk, Virginia, and competed in the East Division of Conference USA (CUSA). The team were coached by second-year head coach Ricky Rahne. On October 27, 2021, Old Dominion announced that this would be the last season for the team in the C-USA and become the Sun Belt Conference on July 1, 2022.