| Sport: | Basketball |
| Year: | 1990–91 |
| Team: | Oklahoma State Cowboys |
| Conference: | Big Eight Conference |
| Short Conf: | Big Eight |
| Coachrank: | 13 |
| Aprank: | 14 |
| Record: | 24–8 |
| Conf Record: | 10–4 |
| Hc Year: | 1st |
| Ac1 Year: | 5th |
| Ac2 Year: | 1st |
| Ac3 Year: | 1st |
| Arena: | Gallagher-Iba Arena (Capacity: 6,381) |
| Champion: | Big Eight Regular season co-champions |
| Bowl Result: | Sweet Sixteen |
The 1990–91 Oklahoma State Cowboys basketball team represented Oklahoma State University as a member of the Big Eight Conference during the 1990–91 NCAA Division I men's basketball season. The team was led by head coach Eddie Sutton and played their home games at Gallagher-Iba Arena. The Cowboys finished with a record of 24–8 (10–4 Big Eight) and won the Big Eight regular season title.
Oklahoma State received an at-large bid to the NCAA tournament as No. 3 seed in the East region. After defeating New Mexico in the opening round, the school's first NCAA Tournament win in 26 years,[1] the Cowboys defeated NC State to reach the Sweet Sixteen. The run ended in the East regional semifinal, as Temple defeated OSU to reach the Elite Eight.
Source:[2]
|-!colspan=9 style=| Non-conference regular season|-!colspan=9 style=| Big Eight regular season|-!colspan=9 style=| Big Eight tournament|-!colspan=9 style=| NCAA tournament
See main article: 1990–91 NCAA Division I men's basketball rankings.