| Year: | 1991 |
| Team: | Oregon State Beavers |
| Sport: | football |
| Conference: | Pacific-10 Conference |
| Short Conf: | Pac-10 |
| Record: | 1–10 |
| Conf Record: | 1–7 |
| Head Coach: | Jerry Pettibone |
| Hc Year: | 1st |
| Off Coach: | Mike Summers |
| Oc Year: | 1st |
| Def Coach: | Rocky Long |
| Dc Year: | 1st |
| Stadium: | Parker Stadium |
The 1991 Oregon State Beavers football team represented Oregon State University in the 1991 NCAA Division I-A football season. The Beavers had one win and ten losses for their twentieth consecutive losing season. They scored 125 and allowed 365 points. The team was led by first-year head coach Jerry Pettibone, previously the head coach for six seasons at Northern Illinois.
The sole victory came in the season finale, a road upset over rival Oregon in the Civil War.
See also: 1991 Oregon Ducks football team and Oregon–Oregon State football rivalry.
Oregon State carried its seniors off the field, a motivational ploy practiced by head coach Jerry Pettibone during the week.