- Obscure (Guía)
- Obscure (PS2)
- Octodad: Dadliest Catch (PC, PS4) ()
- Odin Sphere (PS2)
- Off-World Interceptor Extreme (Playstation)
- Okami (PS2)
- Okami (Wii)
- Okamiden (DS)
- Olympic Hockey 98 (N64)
- Omega Boost (Playstation)
- One Must Fall 2097 (PC)
- One Piece Gigant Battle (DS)
- One Piece Unlimited Cruise SP (3DS)
- One Piece: Grand Adventure (PS2)
- One Piece: Unlimited Aventure (Wii)
- One Piece: Unlimited Cruise (Wii)
- One Step Beyond (PC)
- Oni (PC)
- Oni (PS2)
- Onimusha 2 (PS2)
- Onimusha 3 (PS2)
- Onimusha Dawn of Dreams (PS2)
- Onimusha: Blade Warriors (PS2)
- Onimusha: Warlords (Guía)
- Onimusha: Warlords (PS2)
- Open Season (Wii)
- Operation Flashpoint: Cold War Crisis (PC)
- Operation Flashpoint: Dragon Rising (PC / Xbox 360 / PS3) ()
- Oregon Trail (PC)
- Otomedius Excellent (XBox 360)
- Outer Ridge (PC)
- Outlaws (PC)
- Outrun 2006 Coast 2 Coast (PC)
- Outrun 2006 Coast 2 Coast (PSP)
- Owtlaws (PC)
