| Ivan ORESKOVIC | CRO | 2 Races |
| Juan ORIYES | ESP | 8 Races |
| Ádám ORLIK | HUN | 5 Races |
| German ORLOV | EST | 4 Races |
| Ross ORME | GBR | 4 Races |
| Antonio OROPEZA | VEN | 8 Races |
| Tibor OROSZ | SVK | 2 Races |
| Adrienn OROSZ | HUN | 5 Races |
| Nainoa ORR | USA | 1 Races |
| Lucia ORSULOVÁ | SVK | 16 Races |
| Genevieve Wendy S. ORTON | CAN | 5 Races |
| Genevieve ORTON | CAN | 6 Races |
| Genevieve Wendy Susan ORTON | CAN | 6 Races |
| Moses Ebiegberi ORUGBANI | NGR | 3 Races |
| Moses ORUGBANI | NGR | 5 Races |