| Year: | 1991 |
| Conference: | MAC |
| Division: | I |
| Gender: | Men's |
| Teams: | 8 |
| Arena: | Cobo Arena |
| City: | Detroit, Michigan |
| Champions: | Eastern Michigan |
| Titlecount: | 2nd |
| Coach: | Ben Braun |
| Coachcount: | 2nd |
| Mvp: | Marcus Kennedy |
| Mvpteam: | Eastern Michigan |
The 1991 MAC men's basketball tournament took place March 8–10, 1991, at Cobo Arena in Detroit, Michigan. Eastern Michigan defeated, 67–66 in the championship game, to win its second MAC Tournament title.
The Eagles earned an automatic bid to the 1991 NCAA tournament as #12 seed in the East region. In the round of 64, Eastern Michigan defeated Mississippi State 76–56, and followed that with a 71–68 win over to earn its first NCAA Tournament Sweet Sixteen appearance in program history.
Eight of nine conference members participated, with play beginning in the quarterfinal round. was left out of the tournament field.