| X | 1992 | Nintendo Entertainment Analysis & Development, Argonaut Games | Game Boy |
| X Rebirth | 2013 | Egosoft | Microsoft Windows, macOS, Linux |
| X-COM | 1999 | Hasbro Interactive | Microsoft Windows |
| X-COM: Apocalypse | 1997 | Mythos Games | Microsoft Windows, DOS |
| X-COM: Terror from the Deep | 1995 | MicroProse | PlayStation, Microsoft Windows, DOS, 3DO |
| X-It | 1994 | Data Design Interactive | Commodore Amiga, MS-DOS |
| X-treme Express | 2001 | Syscom Entertainment | PlayStation 2, PlayStation 3 |
| X2 | 1997 | Team17 | PlayStation |
| X2: The Threat | 2003 | Egosoft | Microsoft Windows, macOS, Linux, Mac operating system |
| X2: Wolverine's Revenge | 2003 | — | PlayStation 2, Xbox, Microsoft Windows, Nintendo GameCube, Game Boy Advance |
| X3: Reunion | 2005 | Egosoft | Microsoft Windows, macOS, Linux |
| X3: Terran Conflict | 2008 | Egosoft | Microsoft Windows, macOS, Linux |
| Xanagrams | — | — | Amstrad CPC |
| Xarax | 1988 | — | ZX Spectrum |
| Xbox Fitness | — | Sumo Digital | Xbox One |
| XCOM 2 | 2016 | Feral Interactive, Firaxis Games | Xbox One, Microsoft Windows, macOS, Nintendo Switch, Linux, PlayStation 4 |
| XCOM: Enemy Unknown | 2012 | Feral Interactive, Firaxis Games | PlayStation 3, Microsoft Windows, macOS, Linux, Xbox 360, iOS, Android |
| Xeno | 1986 | — | ZX Spectrum, Commodore 64 |
| Xenocracy | 1998 | — | PlayStation, Microsoft Windows |
| Xenomorph | 1990 | — | Commodore Amiga, DOS, Commodore 64 |
| Xenon | 1988 | The Bitmap Brothers | DOS, ZX Spectrum, Amstrad CPC, MSX, Commodore 64 |
| Xenon 2: Megablast | 1989 | The Assembly Line | Commodore Amiga, Sega Genesis/Mega Drive, DOS, Sega Master System, Acorn Archimedes, Atari ST |
| Xenonauts | 2014 | Goldhawk Interactive | Microsoft Windows, macOS, Linux |
| Xenonauts 2 | 2023 | Goldhawk Interactive | Microsoft Windows |
| XGRA: Extreme G Racing Association | 2003 | Acclaim Studios London | PlayStation 2, Xbox, Nintendo GameCube |
| Xi | 2009 | NDreams | PlayStation 3 |
| Xiaolin Showdown | 2006 | Bottlerocket Entertainment | PlayStation 2, Xbox, Nintendo DS |
| XOR | 1987 | — | ZX Spectrum, Acorn Archimedes, Amstrad CPC, Atari ST, Commodore 64 |
| Xpand Rally | 2004 | Techland | Microsoft Windows |
| Xplora1: Peter Gabriel's Secret World | 1993 | — | Philips CD-i, Classic Mac OS, Microsoft Windows |
| XS | 1996 | Eidos Interactive | Microsoft Windows, DOS |
| Xtreme Racing | 1995 | — | Amiga 1200 |
| X³: Albion Prelude | 2011 | Egosoft | Microsoft Windows, macOS, Linux |