| Surname | Forename | Nationality | Date of Birth |
| O´Born | Francois | – | – |
| O´Brien | Bob | – | – |
| O´Brien | Tom | – | – |
| O´Connor | Pat? | USA | 09.10.1928 |
| O´Dell | Don | – | – |
| O´Halloran | Nick | – | 09.05.1977 |
| O´Neill | Frederic | – | – |
| O´Rourke | Steve | GBR | 01.10.1940 |
| O´Shea | Paul | – | – |
| Ogier | Sebastien | – | – |
| Ojjeh | Karim | – | 27.10.1965 |
| Okamoto | Yukio | JPN | – |
| Oliver | Jacky | GBR | 14.08.1942 |
| “Oloap” (Mario Petrobelli) | – | ITA | – |
| Olofsson | Anders | SWE | 31.03.1952 |
| Olsson | Nigel | – | – |
| Onofre | Marimon | RA | – |
| Ooi | Takayuki | JPN | – |
| Oprey | Michel | NDL | – |
| Oppermann | Jürgen | – | – |
| Orban | Serge | – | – |
| Oreiller | Henri | – | – |
| Oretener | – | – | – |
| Orlandi | M. | – | – |
| Orlando | (Pseudonym) | – | – |
| Orsini | – | – | – |
| Ortega | Guillermo | – | – |
| Ortelli | Stephane | FRA | 30.03.1970 |
| Orts | Michel | – | – |
| Orville | (Pseudonym) | – | – |
| Otha | Tesuya | JPN | – |