Countdown to
000d 00h 00m 00sEntrants
| Entrant | Races | Entries | Starts | Poles | Wins | Podia | F. laps | Pts | |
| 1 | OASC Racing Team | 3 | 3 | ||||||
| 2 | Officine Alfieri Maserati | 44 | 194 | 182 | 9 | 9 | 37 | 15 | 260 |
| 3 | Olympus Cameras Wolf Racing | 15 | 15 | 14 | |||||
| 4 | Olympus Cameras/Hesketh Racing | 6 | 6 | 1 | |||||
| 5 | Onofre Marimón | 1 | 1 | ||||||
| 6 | Orange Arrows | 12 | 24 | 22 | 2 | ||||
| 7 | Orange Arrows Asiatech | 17 | 34 | 34 | 1 | ||||
| 8 | Oreste Berta | 2 | 2 | ||||||
| 9 | OSCA Automobili | 5 | 6 | 3 | |||||
| 10 | Osella Squadra Corse | 156 | 241 | 151 | 7 | ||||
| 11 | Oswald Karch | 1 | 1 | 1 | |||||
| 12 | Otello Nucci | 3 | 5 | 4 | |||||
| 13 | Ottorino Volonterio | 3 | 4 | 4 | |||||
| 14 | Ovoro Team March | 7 | 7 | 5 | |||||
| 15 | Owen Racing Organisation | 128 | 280 | 258 | 9 | 13 | 53 | 11 | 415 |