| title | developer | year | platform | | pop. |
|---|
| Ogre | Origin Systems | 1986 | Apple II E | strategy turn-based Science Fiction | image | | label | |
| Oil Baron | UpTime | 1988 | Apple II E | manag./econ. | | | label | |
| Oil's Well | Banana Development | 1990 | MS-DOS | action/reflex maze | image | | label | |
| Oldtimer | Max Design | 1994 | Amiga | manag./econ. Historical | image | | label | |
| Oldtimer | Max Design | 1994 | Amiga AGA | manag./econ. Historical | image | | label | |
| Omega | Micro Magic | 1989 | Mac OS Classic | strategy Science Fiction | image | | label | |
| Omega: Planete Invisible | Infogrames | 1986 | MSX | adventure role-play Science Fiction | image | | label | |
| On the Ball: World Cup Edition | Ascon | 1994 | Amiga | manag./econ. strategy sport | image | | label | |
| On the Ball: World Cup Edition | Ascon | 1994 | Amiga AGA | manag./econ. strategy sport | image | | label | |
| Once a King | ? | 1988 | Atari ST | adventure | | | label | |
| One Foundation | UpTime | ? | Apple II E | casino/cards | | | label | |
| One-on-One | Electronic Arts | 1985 | Mac OS Classic | sport | image | | label | |
| OpenDune | ? | ? | Pandora | manag./econ. strategy adventure Science Fiction | | | label | |
| Operation Crusader | Atomic Games | 1994 | Mac OS Classic | strategy | | | label | |
| Operation Frog | Interactive Picture Systems | 1992 | MS-DOS | edutainment | | | label | |
| Operation: Desert Storm | Bungie | 1991 | Mac OS Classic | shooter | | | label | |
| Orbiter | Spectrum Holobyte | 1986 | Mac OS Classic | simulation | image | | label | |
| Oscar | Flair Software | 1993 | MS-DOS | platformer | | | label | |
| Outguess | UpTime | 1985 | Apple II E | casino/cards | | | label | |
| Overlord | Rowan Software | 1994 | MS-DOS | simulation flight Historical | image | | label | |
