| Year: | 2005 |
| Team: | Cal Poly Mustangs |
| Sport: | football |
| Conference: | Great West Conference |
| Short Conf: | GWC |
| Tsnrank: | 6 |
| Record: | 9–4 |
| Conf Record: | 4–1 |
| Head Coach: | Rich Ellerson |
| Hc Year: | 5th |
| Off Coach: | Ian Shields |
| Oc Year: | 2nd |
| Stadium: | Mustang Stadium |
| Champion: | GWC co-champion |
| Bowl: | NCAA Division I-AA Quarterfinal |
| Bowl Result: | L 7–14 at Texas State |
The 2005 Cal Poly Mustangs football team represented California Polytechnic State University, San Luis Obispo as member of the Great West Conference (GWC) during the 2005 NCAA Division I-AA football season. Led by fifth-year head coach Rich Ellerson, Cal Poly compiled an overall record of 9–4 with a mark of 4–1 in conference play, sharing the GWC title with UC Davis. The Mustangs advanced to the NCAA Division I-AA Football Championship playoffs, where they defeated Montana in the first round before losing to Texas State in the quarterfinals. The team outscored its opponents 354 to 232 for the season. Cal Poly played home games at Mustang Stadium in San Luis Obispo, California.
The following Cal Poly Mustang players were selected in the 2006 NFL draft.[3] [4] [5]
| Player | Position | Round | Overall | NFL team | |
| Defensive end | 3 | 71 | Philadelphia Eagles |