The 1984–85 Illinois State Redbirds men's basketball team represented Illinois State University during the 1984–85 NCAA Division I men's basketball season.

The Redbirds, led by seventh year head coach Bob Donewald, played their home games at Horton Field House and were a member of the Missouri Valley Conference.

They were the number two seed for the Missouri Valley Conference tournament by virtue of sweeping the season series over Wichita State University.

They were defeated in a quarterfinal game to Indiana State University.

The Redbirds received an at-large bid to the 1985 NCAA Division I men's basketball tournament.