The 1990–91 Michigan State Spartans men's basketball team represented Michigan State University in the 1990–91 NCAA Division I men's basketball season. The team played their home games at Breslin Center in East Lansing, Michigan and were members of the Big Ten Conference. They were coached by Jud Heathcote in his 15th year at Michigan State. The Spartans finished the season with a record of 19–11, 11–7 to finish in third place in Big Ten play. They received an at-large bid as a No. 5 seed to the NCAA Tournament where they beat Green Bay on a buzzer beater by Steve Smith. In the Second Round, they lost to No. 10 Utah in double overtime, 84–85.