The 1991 Western Michigan Broncos football team represented Western Michigan University in the Mid-American Conference (MAC) during the 1991 NCAA Division I-A football season. In their fifth season under head coach Al Molde, the Broncos compiled a 6–5 record (4–4 against MAC opponents), finished in fifth place in the MAC, and were outscored by their opponents, 253 to 218. The team played its home games at Waldo Stadium in Kalamazoo, Michigan.