The 1986 Illinois State Redbirds football team represented Illinois State University as a member of the Gateway Collegiate Athletic Conference (GCAC) during the 1986 NCAA Division I-AA football season. In their sixth year under head coach Bob Otolski, the Redbirds compiled an overall record of 5–5, with a mark of 3–3 in conference play, and placed fourth in the GCAC. Illinois State played home games at Hancock Stadium in Normal, Illinois.