| Company | Country | Founded | Games developed | Games published |
|---|---|---|---|---|
| X Plus | Japan | 1986 | — | 1 |
| Xaloc Studios | Spain | 2015 | 4 | — |
| XAX Entertainment, Inc. | Japan | April 4, 1996 | 1 | — |
| Xbox Game Studios | United States | March 2000 | 14 | 164 |
| XD | People's Republic of China | 2010 | 2 | 6 |
| Xeen | Japan | July 3, 2006 | 1 | — |
| Xemono | Japan | April 2019 | 1 | — |
| Xform Games | Netherlands | June 28, 2004 | 4 | 2 |
| XGen Studios | Canada | 2001 | 3 | 2 |
| Xigma Games | India | — | 3 | 2 |
| Germany | 2003 | — | — | |
| Xitilon | Ukraine | — | 1 | 10 |
| XLGames | South Korea | April 2003 | 4 | 1 |
| XPEC Entertainment | Taiwan | August 2000 | 3 | 1 |
| XS Games | United States | 2002 | — | 2 |
| Xseed Games | United States | 2004 | — | 27 |
| Xtalsoft | Japan | 1982 | 1 | 1 |
| Xuse | Japan | November 1998 | 2 | 1 |