| 44902 | Obstáculos | ZX-Spectrum 16K | Spanish |
| 30638 | Octopus Lite | ZX-Spectrum 16K | English |
| 37634 | Octopus Mating Simulator | ZX-Spectrum 16K | English |
| 10010 | Odds on | ZX-Spectrum 16K | English |
| 3491 | Odyssey 1 | ZX-Spectrum 16K | English |
| 30587 | Official Hearing Test | ZX-Spectrum 16K | English |
| 20395 | Oglibloggs + Laser Defence | ZX-Spectrum 16K | English |
| 3494 | Oh Mummy | ZX-Spectrum 16K | English |
| 31070 | Oh My God! | ZX-Spectrum 16K | English |
| 18444 | Old Bones | ZX-Spectrum 16K | English |
| 44932 | Olimpia 3D | ZX-Spectrum 16K | Spanish |
| 8518 | Ollie Octopus' Sketchpad | ZX-Spectrum 16K | English |
| 40944 | Olympia | ZX-Spectrum 16K | English |
| 26933 | Omega Invaders | ZX-Spectrum 16K | English |
| 16963 | On-Error-Goto | ZX-Spectrum 16K | English |
| 34701 | One Kick | ZX-Spectrum 16K | English |
| 39402 | One Line Snake | ZX-Spectrum 16K | Multi-language: English, Spanish |
| 27510 | OpenSE BASIC | ZX-Spectrum 16K | English |
| 26934 | Opening Up Graphics | ZX-Spectrum 16K | English |
| 44715 | Operation Bee | ZX-Spectrum 16K | English |