| Region | Title | System | Version | Edition | Languages | Serial | Status |
|---|
 | Operation Neptune + Reader Rabbit 2 Deluxe! + Ultimate Writing & Creativity Center
The Learning Company 3-in-1 | PC | | |  | |  |
| Operation Omega | PC | | Original | | 7-20286-92175-1 | |
| The Operational Art of War: Century of Warfare | PC | | Original | | | |
| The Operative: No One Lives Forever (Disc 1) | PC | | Bundle Version Micro-Star International OEM |     | CD-W581995-MSYZ1, FXX08903223D1 | |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.0 | Original | | | ![2 and more dumps from original media [!]](/images/status/green.png "2 and more dumps from original media [!]") |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.004 | Game of the Year Edition | | | |
| The Operative: No One Lives Forever (Disc 2) (In the Lounge with No One Lives Forever) | PC | | Bundle Version Micro-Star International OEM | | CD-W581995-MSYZ2 | |
| The Operative: No One Lives Forever (Disc 2) | PC | 1.0 | Original | | | |
| Opsys | PC | | Original | | | |
| Optimum Resource Sampler | PC | | Rerelease | | | |
| Optimum Resource Sampler | PC | | Original | | | |
| The Orange Box (Disc 2) | PC | | Original |        | 985217 | |
| Orchid Technology Kelvin MPEG Software Catalog | PC | | | | | |
| The Oregon Trail 3rd Edition: Pioneer Adventures | PC | 1.0 | DVD-ROM | | ORG811AE-DVD | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 1) | PC | 1.0 | Original | | OTA744AE-CD1 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 1) | PC | 1.2 | Original | | OTA744CE-CD1 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 1) | PC | 1.2 | Rerelease | | OTA744BE-CD1 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 1) | PC | 1.2a | Bundle Version Compaq Presario OEM | | | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 1) | PC | 1.3 | The Learning Company | | OAE744BE-CD1 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 2) | PC | | Original | | OTA744AE-CD2 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 2) | PC | 1.2 | Original | | OTA744BE-CD2 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 2) | PC | 1.3 | The Learning Company | | OAE744BE-CD2 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 3) | PC | | Original | | OTA744AE-CD3 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 3) | PC | | Original | | OTA744AE-CD3 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 3) | PC | 1.2 | Original | | OTA744BE-CD3 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 3) | PC | 1.3 | The Learning Company | | OAE744BE-CD3 | |
| The Oregon Trail 4th Edition (Disc 1) | PC | 1 | Original | | OTF744AE-CD1 | |
| The Oregon Trail 4th Edition (Disc 1) | PC | 1.1 | Rerelease | | OTF744BE-CD1 | |
| The Oregon Trail 4th Edition (Disc 2) | PC | 1 | Rerelease | | OTF744CE-CD2 | |
| The Oregon Trail 4th Edition (Disc 2) | PC | 1 | Original | | OTF744AE-CD2 | |
| The Oregon Trail 4th Edition (Disc 2) | PC | 1.1 | Rerelease | | OTF744BE-CD2 | |
| The Oregon Trail 4th Edition (Disc 3) | PC | 1 | Original | | OTF744AE-CD3 | |
| The Oregon Trail 4th Edition (Disc 3) | PC | 1.1 | Rerelease | | OTF744BE-CD3 | |
| The Oregon Trail 5th Edition: Adventures Along the Oregon Trail | PC | 1.0 | Original | | 380859-CD | |
| The Oregon Trail 5th Edition: Adventures Along the Oregon Trail | PC | 1.0 | Scholastic | | 380859-CD WP2 | |
| The Oregon Trail 5th Edition: Adventures Along the Oregon Trail | PC | 1.0 | Original | | 380859A-CD | |
| The Oregon Trail 5th Edition: Adventures Along the Oregon Trail | PC | 1.01E | Enhanced Education Version | | 480599-CD | |
| The Oregon Trail 5th Edition: Adventures Along the Oregon Trail | PC | 1.1 | Rerelease, Southwestern School Set | | 380859B-CD | |
| Oregon Trail II | PC | 1.0 | Original | | | |
| Oregon Trail II | PC | 1.3 | Smart Saver | | 0TT744AE-CD | |
| Oregon Trail II | PC | 1.3 | Smart Saver | | 381032-CD/i401ha | |
| Oregon Trail II | PC | 1.31 | Rerelease | | HCD744BE-CD | |
| Oregon Trail II | PC | 1.31 | Rerelease | | #HCD744AE-CD | |
| Oregon Trail II | PC | 1.32 | Rerelease | | #HCD744CE-CD | |
| Oregon Trail II + Logic Quest | PC | 1.2/1.0 | Original | | | |
| Oregon Trail II: 25th Anniversary Limited Edition | PC | 1.3 | Original, SoftKey | | #OTR744AE-CD | |
| The Oregon Trail | PC | 1.0 | Original | | | |
| The Oregon Trail | PC | 1.1 | Original | | #HCD606 | |
| The Oregon Trail | PC | 1.2 | Original | | #HCD706 | |
| The Oregon Trail | PC | 1.2 | Original | | #HCD706 | |
| The Oregon Trail | PC | 1.21 | | | | |
| The Oregon Trail | PC | 1.22 | Smart Saver | | ORT844AE-CD | |
| The Oregon Trail | PC | 3.0.1 | Slash | | CDRM1239790 | |
| The Oregon Trail: Classic Edition | PC | | SoftKey | | POT144EE-CD | |
| The Oregon Trail: Classic Edition | PC | | SoftKey | | POT144BE-CD | |
| The Oregon Trail: Classic Edition | PC | 3.0.1 | SoftKey | | POT144CE-CD | |
| The Original Links | PC | | Solid Gold Edition | | | |
| The Original Mulan
花木兰 | PC | | Original | | | |
| The Orion Conspiracy | PC | 1.01 | Original | | | |
| Orly's Draw-A-Story | PC | | Original | | | |
| Oscar Wilde's The Selfish Giant | PC | 2.10 | Original | | MQ 13-004-144 | |
| Othello | PC | | Original |  | 99011 | |
| Out of This World | PC | | Valueware | | CD-ICD-142-0 | |
| Out of This World | PC | | Rerelease | | CD-MMC-023-0 | |
| Outburst | PC | | Classic Value Series | | Product# 99043 | |
| Outcast (Disc 1) | PC | | Original | | 42831-9110TC | |
| Outcast (Disc 2) | PC | | Original | | 42831-9110TC | |
| Outcry (Disc 1)
Outcry: The Dawn | PC | Version DPV 1.0 | Original | | PCO596CD | |
| Outcry (Disc 2)
Outcry: The Dawn | PC | Version DPV 1.0 | Original | | PCO596CD | |
| Outlast: A Reading for Information Game | PC | | Original | | HH824 | |
| Outlaws (Demonstration Program) | PC | Demo 1.0 CD Build 3 | Demo | | 644230 | |
| Outlaws (Disc 1) | PC | 1.0 Build 3 | Original | | 9511830 | |
| Outlaws (Disc 1) | PC | 1.0 Build 3 | Bundle Version Diamond OEM | | 644430 | |
| Outlaws (Disc 1) | PC | 2.0 | Rerelease | | 9511830 | |
| Outlaws (Disc 1) | PC | 2.0 | Rerelease | | 9511830 | |
| Outlaws (Disc 1) | PC | 2.0 | Rerelease | | 9511830 | |
| Outlaws (Disc 2) | PC | 1.0 Build 3 | Original | | 9511831 | |
| Outlaws (Disc 2) | PC | 1.0 Build 3 | Bundle Version Diamond OEM | | 644431 | |
| Outlaws (Disc 2) | PC | 2.0 | Rerelease | | 9511831 | |
| Outlaws (Disc 2) | PC | 2.0 | Rerelease | | 9511831 | |
| Outlaws (Disc 2) | PC | 2.0 | Rerelease | | 9511831 | |
| Outlive | PC | 1.01 | Original | | | |
| Outpost | PC | | Original | | S725430 | |
| Outpost | PC | 1.1 | Rerelease | | S725431 | |
| Outpost | PC | 1.5 | Rerelease, Sierra Originals | | | |
| Outpost 2: Divided Destiny | PC | 1.2.0.5 | Original | | | |
| Outpost 2: Divided Destiny | PC | 1.2.0.5 | Original | | | |
| OutRun 2006: Coast 2 Coast (Disc 1) | PC | | Original | | | |
| OutRun 2006: Coast 2 Coast (Disc 2) | PC | | Original | | | |
| Outwars (Disc 1) | PC | 1.0 | Original | | 0298 Part No. X03-63527 | |
| Outwars (Disc 2) | PC | 1.0 | Original | | 0298 Part No. X03-57509 | |
| Overlord | PC | 1.0 | Original | | MOVL1CDFC00 | |
| Overlord II | PC | | Preview Code |    | | |
| Overlord II | PC | 1.0 | Original | | MOVL2CDUS00 | |
| Overwatch | PC | | Game of the Year Edition, Legendary Edition | | 73052010US, S7302210 | |
| Owlboy (Game Disc) | PC | 0.0.6152.604 | IndieBox | | | |
| Oz: The Magical Adventure | PC | | Original | | | |
| Oz: The Magical Adventure | PC | 7.0.0.198 | Rerelease | | 92785 | |
| Ozzie's World | PC | | Original | | | |
 | Overwatch | PC | | Origins Edition | | | |
 | The Official Guide to The Daedalus Encounter: Companion Disc | PC | | Original | | | |
| Oil Tycoon | PC | 1.01 | Original | | | |
| Ori and the Blind Forest: Definitive Edition | PC | 5.3.2.9582331 | Limited Edition | | | |
| Over 1000 Games: The Complete Encyclopedia of Games (Disc 1) | PC | | Original | | | |
| Over 1000 Games: The Complete Encyclopedia of Games (Disc 2) | PC | | Original | | | |
 | Operation Flashpoint: Gold Upgrade | PC | 1.30 | Original, Gold Edition | | MOFUCDEU00, MOFUCDUS00 | |
| The Operative: No One Lives Forever (Disc 2) | PC | 1.004 | Game of the Year Edition, Game of the Year Edition (BestSeller Series), Game of the Year Edition (Covermount) | | JCPL11, S0026179, S0026696 | |
| The Orange Box (Disc 1) | PC | | Original, EA Classics | | 985207, VAE07705811D, VAE07705811D/ENG, VAE07707118D/ENG, VAX07705811D/AUS | |
 | The Operational Art of War II | PC | 1.01.02 | Xplosiv | | EI-1259-3 | |
 | The Orange Box (Disc 2) | PC | | Original, EA Classics | | VAE07705811D2/ENG, VAE07707118D2/ENG, VAX07705811D2, VAX07705811D2/AUS | |
