| Name | Nation |
|---|---|
| O'Bee, Kirk | USA |
| O'Grady, Stuart | AUS |
| O'Loughlin, David | IRL |
| O'Neill, Nathan | AUS |
| Oarbeascoa Ispizua, Ruben | ESP |
| Obrist, Gilbert | SUI |
| Obst, René | GER |
| Obwaller, Hans Peter | AUT |
| Odebrecht, Felix | GER |
| Oeschger, Peter | SUI |
| Ogris, Vid | SLO |
| Ojavee, Mart | EST |
| Okazaki, Kazuya | JPN |
| Okrucinski, Daniel | POL |
| Olde Dubbelink, Peter | NED |
| Oliphant, Evan | GBR |
| Oliveira, Helder | POR |
| Oliveira, Alexandre | POR |
| Olivier, Lénaïc | FRA |
| Ollerenshaw, Doug | USA |
| Olmo, Jose Maria | ESP |
| Olmo Menacho, Juan | ESP |
| Olmo Menacho, Antonio | ESP |
| Olson, Aaron | USA |
| Olszewski, Daniel | GER |
| Omloop, Geert | BEL |
| Omulec, Andrej | SLO |
| Ongarato, Alberto | ITA |
| Ongena, Thomas | BEL |
| Oostvogels, Gert-Jan | BEL |
| Oouchi, Kaoru | JPN |
| Ordowski, Volker | GER |
| Oriol, Christophe | FRA |
| Ortiz Ortiz, Nilton Alexis | COL |
| Ortner, Andreas | GER |
| Osa Eizaguirre, Aitor | ESP |
| Osa Eizaguirre, Unai | ESP |
| Osella, Marco | ITA |
| Osinski, Marcin | POL |
| Oswald, Benedikt | AUT |
| Otxotorena Arraras, Xabat | ESP |
