- OROBOROS
- Os Caçadores de Lendas
- Oscar Adventure
- Osmanische Ghazi-Kriegerlegend
- Osmanischer Krieger des Osmani
- Osmo in Space
- OsterGlück Gütersloh
- Osu Ninja Split
- OTEDAMA
- Otherworld Legends
- Otherworldly Zombies
- Otobüs Simülasyonu
- Otter Evolution - Furry Sea Mutant Seal Breeding
- Kriege des Osmanischen Reiches
- Ouch! Lite
- Ouro
- Out Of The Way TV
- Outbreak Unlimited
- Outbreak Unlimited
- Outbreak: The Zombie Slayer
- OUTDODGE
- Outer Space Battle 2
- Outer-Space
- Outfire: Battle Royale Shooter
- Outlaw Gliders
- Outlaw Riders: Biker Wars
- Outleap!
- Außenposten Mars 2050
- Outrun da Rail
- OutRush - Synthwave Action
- OuttaMyWay! Lights & Sirens
- Over Midway
- Over The Bridge
- Over What Kill
- Overclock the Game