- O.D.T. (Guia)
- O.D.T. (PC)
- O.D.T. (PSX)
- O.R.B. (PC)
- Obscure (Guia)
- Obscure (PS2)
- Oddworld Adventures (Game Boy)
- Odin Sphere (PS2)
- Off-Road Challenge (Nintendo 64)
- Off-World Interceptor Extreme (PSX)
- Okami (PS2)
- Okami (Wii)
- Okamiden (DS)
- Olympic Hockey 98 (Nintendo 64)
- Omega Boost (PSX)
- Omikron: The Nomad Soul (Dreamcast)
- Omikron: The Nomad Soul (Guia)
- One (PSX)
- One Must Fall 2097 (PC)
- One Piece Gigant Battle (DS)
- One Piece Mansion (PSX)
- One Piece: Grand Adventure (PS2)
- One Piece: Unlimited Aventure (Wii)
- One Piece: Unlimited Cruise (Wii)
- One Step Beyond (PC)
- One Unit Whole Blood (PC)
- One on One (PSX)
- Oni (PC)
- Oni (PS2)
- Onimusha 2 (PS2)
- Onimusha 3 (PS2)
- Onimusha Dawn of Dreams (PS2)
- Onimusha: Blade Warriors (PS2)
- Onimusha: Warlords (Guia)
- Onimusha: Warlords (PS2)
- Ooga Booga (Dreamcast)
- Open Season (Wii)
- Operation C (Game Boy)
- Operation Flashpoint: Cold War Crisis (PC)
- Operation Flashpoint: Dragon Rising (PC / Xbox 360 / PS3) (Trucos)
- Operation Flashpoint: Resistance (PC)
- Operation Thunderbolt (PC)
- Operation Wolf (PC)
- Option Tuning Car Battle 2 (PSX)
- Oregon Trail (PC)
- Orphen: Scion of Sorcery (PS2)
- Otomedius Excellent (XBox 360)
- Out Of This World (PC)
- Out Trigger (Dreamcast)
- Outcast (PC)
- Outer Ridge (PC)
- Outlaw Golf (XBox)
- Outlaws (PC)
- Outlive (PC)
- Outpost (PC)
- Outpost 2 (PC)
- Outrun (PC)
- Outrun 2006 Coast 2 Coast (PC)
- Outrun 2006 Coast 2 Coast (PS2)
- Outrun 2006 Coast 2 Coast (PSP)
- Outrun 2006 Coast 2 Coast (XBox)
- Outwars (PC)
- Overblood (PSX)
- Overblood 2 (PSX)
- Overboard (PC)
- Overboard (PSX)
- Owtlaws (PC)
- Oxyd (PC)
