| 3478 | Obliterator | ZX-Spectrum 48K/128K | English |
| 30210 | Oceano | ZX-Spectrum 48K/128K | English |
| 3487 | Octopussy | ZX-Spectrum 48K/128K | Slovak |
| 34636 | Octukitty | ZX-Spectrum 48K/128K | English |
| 25145 | Oddi the Viking | ZX-Spectrum 48K/128K | - |
| 34458 | Old Tower | ZX-Spectrum 48K/128K | English |
| 9385 | Olli & Lissa 3 | ZX-Spectrum 48K/128K | English |
| 1395 | Omega Dimension | ZX-Spectrum 48K/128K | Spanish |
| 34676 | Operation - Labyrinth Fall | ZX-Spectrum 48K/128K | English |
| 9386 | Operation Gunship | ZX-Spectrum 48K/128K | English |
| 10017 | Operation Gunshot | ZX-Spectrum 48K/128K | English |
| 3528 | Operation Hanoi | ZX-Spectrum 48K/128K | English |
| 3530 | Operation Hormuz | ZX-Spectrum 48K/128K | English |
| 3532 | Operation Thunderbolt | ZX-Spectrum 48K/128K | English |
| 3534 | Operation Wolf | ZX-Spectrum 48K/128K | English |
| 42674 | Orbol Voon | ZX-Spectrum 48K/128K | Multi-language: English, Spanish |
| 8524 | Organ Master | ZX-Spectrum 48K/128K | English |
| 3544 | Oriental Games | ZX-Spectrum 48K/128K | English |
| 43608 | Osotos | ZX-Spectrum 48K/128K | English |
| 12693 | Our Life 3 | ZX-Spectrum 48K/128K | Russian |