The 2005–06 Illinois State Redbirds men's basketball team represented Illinois State University during the 2005–06 NCAA Division I men's basketball season.

The Redbirds, led by third year head coach Porter Moser, played their home games at Redbird Arena and competed as a member of the Missouri Valley Conference.

They finished the season 9–19, 4–14 in conference play to finish in a tie for ninth place.

They were the number ten seed for the Missouri Valley Conference tournament.

They were defeated by the University of Evansville in their opening round game.