The 2020–21 Illinois State Redbirds men's basketball team represented Illinois State University during the 2020–21 NCAA Division I men's basketball season. The Redbirds, led by ninth-year head coach Dan Muller, played their home games at Doug Collins Court at Redbird Arena in Normal, Illinois as members of the Missouri Valley Conference. In a season limited due to the ongoing COVID-19 pandemic, they finished the season 7–18, 4–14 in MVC play to finish in 10th place. In the MVC tournament, they lost to Northern Iowa in the first round.