Game Boy Advance - O
- Oddworld - Munch's Oddysee
- One Piece
- One Piece - Dragon Dream
- One Piece - Going Baseball
- One Piece - Grand Battle
- One Piece - Mezase! King of Paris
- One Piece - Nanatsu Shima No Daihihou
- Onimusha Blade Warriors
- Onimusha Tactics
- Open Season
- Operation Armored Liberty
- Over the Hedge
- Over the Hedge - Hammy Goes Nuts
- Ozzy & Drix
- Ozzy and Drix