| O'Leary Manager 2000 |
| Obelix |
| Oddworld Adventures II |
| Odoru Tensai Pet! - Dancing Furby |
| Ohasuta Dance Dance Revolution GB |
| Ohasuta Yamachan & Raymond |
| Oide Rascal |
| Ojarumaru - Mitsunegai Jinja no Ennichi de Ojaru! |
| Ojarumaru - Tsukiyo ga Ike no Takaramono |
| Original Moorhuhn Jagd, Die |
| Oshare Nikki |
| Othello Millennium |
| Other Life - Azure Dreams GB |
| Ottifanten - Kommando Stoertebeker |
| Ou Dorobou Jing |
| Ou Dorobou Jing - Angel Version |
| Ou Dorobou Jing - Devil Version |
| Owarai Yowiko no Game-dou - Oyaji Sagashite Sanchoume |
