Players ATPWTA
| Name | Country |
|---|---|
| Haine Ogata | JPN |
| Inci Ogut | TUR |
| Chiaki Okadaue | JPN |
| Martina Okalova | SVK |
| Kyoka Okamura | JPN |
| Akiko Okuda | USA |
| Ayaka Okuno | JPN |
| Barbara Oliveira | BRA |
| Giuliana Olmos | MEX |
| Akiko Omae | JPN |
| Erica Oosterhout | USA |
| Romina Oprandi | SUI |
| Paula Ormaechea | ARG |
| Maja Ornberg | SWE |
| Mari Osaka | JPN |
| Naomi Osaka | JPN |
| Maria Camila Osorio Serrano | COL |
| Jelena Ostapenko | LAT |
| Fanny Ostlund | SWE |
| Whitney Osuigwe | USA |
| Sara Ottomano | SUI |
| Melanie Oudin | USA |
| Sofie Oyen | BEL |
| Risa Ozaki | JPN |
| Michika Ozeki | JPN |
| Justine Ozga | GER |
| Pemra Ozgen | TUR |