| Jamesboy OINAM | IND | 5 Races |
| Ali OJAGHI | IRI | 10 Races |
| Furntes OJAY | PHI | 1 Races |
| John OLANDER | SWE | 3 Races |
| Maria OLARASU | MLD | 31 Races |
| Mark OLDERSHAW | CAN | 10 Races |
| Mark William OLDERSHAW | CAN | 13 Races |
| Vladislav OLEYNIKOV | RUS | 10 Races |
| Andrej OLIJNIK | LTU | 31 Races |
| Scarlet OLIVA | CHI | 2 Races |
| Ronilson OLIVEIRA | BRA | 7 Races |
| Ronilson Matias OLIVEIRA | BRA | 3 Races |
| André OLIVEIRA | ESP | 16 Races |
| Ronilson Matias de OLIVEIRA | BRA | 3 Races |
| Vitor OLIVEIRA | POR | 3 Races |