| 25868 | OXO | ZX-Spectrum 48K | English |
| 18413 | OXO | ZX-Spectrum 16K | English |
| 19549 | OXO Addition and Subtraction | ZX-Spectrum 48K | English |
| 19550 | OXO Anagrams | ZX-Spectrum 48K | English |
| 19551 | OXO Multiplication and Division | ZX-Spectrum 48K | English |
| 12692 | Oasis 1 | ZX-Spectrum 48K | English |
| 3478 | Obliterator | ZX-Spectrum 48K/128K | English |
| 3481 | Oblivion | ZX-Spectrum 48K | English |
| 41206 | Obstacle Course | ZX81 16K | English |
| 42963 | Obstacle Course | ZX-Spectrum 48K | English |
| 23069 | Occupations Clipart | ZX-Spectrum 48K | English |
| 6754 | Ocean Dancer | ZX-Spectrum 48K | English |
| 24292 | Ocean Defence | ZX-Spectrum 48K | English |
| 29140 | Ocean Trader | ZX81 16K | English |
| 14274 | Ocean's Greatest Hits | ZX-Spectrum 48K | English |
| 30210 | Oceano | ZX-Spectrum 48K/128K | English |
| 3483 | Octagon | ZX-Spectrum 48K | English |
| 3484 | Octagon Squad | ZX-Spectrum 48K | English |
| 3485 | Octan | ZX-Spectrum 48K | English |
| 3486 | Octipede | ZX-Spectrum 48K | English |