* ObsCure
* The Official Game: World Series of Poker
* Okage: Shadow King
* Okami
* One Piece Grand Adventure
* One Piece Grand Battle
* One Piece: Pirates Carnival
* Oni (Bungie)
* Onimusha: Warlords (Capcom)
* Onimusha 2: Samurai's Destiny (Capcom)
* Onimusha 3: Demon Siege (Capcom)
* Onimusha Blade Warriors (Capcom)
* Onimusha: Dawn of Dreams (Capcom)
* Open Season
* The Operative: No One Lives Forever (Monolith)
* Orphen: Scion of Sorcery
* Outlaw Golf
* Outlaw Golf 2
* Outlaw Tennis
* Outlaw Volleyball Remixed
* OutRun 2006: Coast 2 Coast
* Over the Hedge
