| Title | Platform | Genre | Release Date |
|---|---|---|---|
| O.R.B.: Off-World Resource Base | PC | Strategy | Nov 4, 2002 |
| Obscure | PS2, XBOX, PC, PSP | Action | Mar 31, 2005 |
| Obscure: The Aftermath | PS2, WII | Action Adventure | Mar 27, 2008 |
| Octodad | PC | Action Adventure | Nov 1, 2010 |
| Octodad: Dadliest Catch | PC, MAC, PS4, LINUX | Action Adventure | Jan 30, 2014 |
| Octomania | WII | Action | Mar 25, 2008 |
| Oddworld: Abe's Exoddus | PSONE, PC | Platform | Oct 31, 1998 |
| Oddworld: Abe's Oddysee | PSONE, PC | Platform | Aug 31, 1997 |
| Oddworld: Abe's Oddysee - New 'n' Tasty | PSVITA, PS3, PC, X360, PS4, MAC, LINUX, WIIU | Platform | na |
| Oddworld: Munch's Oddysee | XBOX, PC, PS3, PSVITA | Action | Nov 15, 2001 |
| Oddworld: Stranger's Wrath | XBOX, PC, PS3, PSVITA | Action | Jan 25, 2005 |
| Odin Sphere | PS2 | Action Adventure | May 23, 2007 |
| Of Orcs and Men | PC, PS3, X360 | RPG | Oct 11, 2012 |
| Off-Road Drive | PC | Other | Sep 29, 2011 |
| Off-Road Velociraptor Safari | PC | Action | Jan 28, 2008 |
| Office Space | PSP MOVIE | Other | na |
| Officers | PC | Strategy | Mar 24, 2009 |
| Offspring Fling | PC, MAC | Puzzle | Mar 30, 2012 |
| Ogre Battle 64: Person of Lordly Caliber | WII | RPG | Mar 29, 2010 |
| Ogre Battle: The March of the Black Queen | WII | RPG | Mar 2, 2009 |
| Ohno Odyssey | 3DS | Puzzle | Nov 21, 2013 |
| Oil Rush | MAC, LINUX | Strategy | Jan 25, 2012 |
| OIO: The Game | PC | Platform | na |
