| Name | Nation |
|---|---|
| O'Bee, Kirk | USA |
| O'Brien, Paidi | IRL |
| O'Brien, Mark | AUS |
| O'Grady, Stuart | AUS |
| O'Loughlin, David | IRL |
| O'Reilly, Cody | USA |
| O'Shea, Glenn | AUS |
| Oberholzer, Bernhard | SUI |
| Obst, René | GER |
| Ochoa, Carlos José | VEN |
| Ockeloen, Jasper | NED |
| Offredo, Yoann | FRA |
| Ogris, Vid | SLO |
| Oh, Seong Youn | KOR |
| Ojavee, Mart | EST |
| Oka, Toyohiro | JPN |
| Okazaki, Kazuya | JPN |
| Okrouhlicky, Tomas | CZE |
| Olano Orbegozo, Aitor | ESP |
| Olesen, Nicolaj | DEN |
| Oliphant, Evan | GBR |
| Oliveira, Helder | POR |
| Oliveira, Alexandre Candido | POR |
| Oliveira Amorim, Antonio Filipe | POR |
| Olmo Menacho, Antonio | ESP |
| Olson, Aaron | USA |
| Omloop, Geert | BEL |
| Ongarato, Alberto | ITA |
| Ongena, Thomas | BEL |
| Onghena, Matthias | BEL |
| Oredsson, Thomas | DEN |
| Oroz Ugalde, Juan Jose | ESP |
| Ortega, Didac | ESP |
| Ortega Ocana, Manuel | ESP |
| Oseda Sana, Santiago | COL |
| Osinski, Piotr | POL |
| Osip, Antonio | CRO |
| Oss, Daniel | ITA |
| Oste Macdonald, Max | SWE |
| Ostergaard, Niki | DEN |
| Ovechkin, Artem | RUS |
