| THQ | April 1990 | 9 | 151 |
| THQ Wireless | — | 1 | 2 |
| Three-Sixty Pacific | 1987 | 2 | 2 |
| Tiger Electronics | 1978 | 1 | — |
| Tigon Studios | 2002 | — | 1 |
| TikGames | 2002 | 1 | 1 |
| Tilted Mill Entertainment | 2001 | 3 | — |
| Time Warner Interactive | 1993 | 1 | 1 |
| TimeGate Studios | 1998 | 3 | 1 |
| TKO Software | 2002 | 1 | — |
| ToeJam & Earl Productions | 1989 | 3 | — |
| Tommo Inc. | 1989 | — | 2 |
| Top Hat Studios | — | — | 14 |
| Totally Games | 1984 | 16 | — |
| Touchstone Pictures | February 15, 1984 | — | 1 |
| Toys for Bob | 1989 | 14 | — |
| Tradewest | 1986 | — | 9 |
| Treyarch | 1996 | 15 | — |
| Tri Synergy | 1996 | — | 3 |
| Tribe Games | 2009 | 1 | — |
| Tribetoy | 2008 | 1 | 1 |
| Trion Worlds | January 10, 2005 | 1 | 1 |
| Triple.B.Titles | — | 1 | — |
| Tripwire Interactive | 2005 | 3 | 4 |
| Troika Games | 1998 | 1 | — |
| Tsunami Games | 1991 | 1 | — |
| Turn 10 Studios | 2001 | 8 | — |
| Twin Otter Studios | November 14, 2020 | 1 | — |
| Twisted Dragon Media | — | 1 | 1 |
| Twisted Pixel Games | 2006 | 1 | — |
| Twitch Interactive | September 18, 2006 | — | 1 |
| UFO Interactive Games | 1999 | — | 4 |
| Ultra Games | 1988 | — | 7 |
| Undead Labs | November 23, 2009 | 1 | — |
| Underground Development | 1994 | 3 | — |
| United States Army | June 14, 1775 | 2 | 1 |
| Unity Technologies | August 2, 2004 | — | — |
| Unknown Worlds Entertainment | 2001 | 2 | 2 |
| Utopos Games | — | — | 1 |
| Uvula | — | 1 | — |
| Valcon Games | 2005 | — | 2 |
| Valve Corporation | 1996 | 30 | 28 |
| Vector Unit | 2007 | 4 | 3 |
| Venan Entertainment | 2002 | 1 | — |
| Veritable Joy Studios | — | 1 | 1 |
| Versus Evil | 2013 | — | 17 |
| Viacom | December 31, 2005 | — | 2 |
| Vicious Cycle Software | 2000 | 4 | — |
| Vigil Games | 2005 | 3 | — |
| Virgin Interactive | 1983 | 1 | 34 |
| Visceral Games | 1998 | 15 | — |
| Visual Concepts | 1988 | 55 | — |
| Viz Media, LLC | July 2, 1986 | — | 1 |
| Wadjet Eye Games | 2006 | 5 | 8 |
| Wahoo Studios | 2001 | 1 | — |
| Waking Oni Games | — | 1 | — |
| Walt Disney Animation Studios | October 16, 1923 | — | — |
| Walt Disney Records | 1956 | — | 1 |
| Wargaming Seattle | — | 7 | — |
| Warner Bros. Entertainment | April 4, 1923 | — | 2 |
| Warner Bros. Games | 2004 | 3 | 66 |
| WayForward Technologies | 1990 | 24 | 12 |
| WB Games Boston | 1994 | 1 | — |
| Webfoot Technologies | 1993 | 4 | — |
| Westwood Studios | 1992 | 19 | 2 |
| WhaleFood Games | 2013 | 1 | — |
| Whiptail Interactive | — | — | 4 |
| WhiteMoon Dreams | 2007 | 1 | — |
| Whitethorn Games | 2016 | 1 | 13 |
| Wide Right Interactive | 2017 | 3 | 3 |
| WildTangent | 1998 | 3 | 2 |
| WildWorks | — | 1 | — |
| Will Winn Games | 2020 | 1 | 1 |
| Wizards of the Coast | 1990 | — | 2 |
| WizardWorks Software | August 21, 1980 | — | 9 |
| WMS Industries | 1974 | 1 | 4 |
| Wolfire Games | 2003 | 1 | 1 |
| Working Designs | 1986 | — | 4 |
| World of Wonder | 1991 | — | 1 |
| Worldwalker Games | — | 1 | 1 |
| Xbox Game Studios | March 2000 | 14 | 164 |
| XS Games | 2002 | — | 2 |
| Xseed Games | 2004 | — | 27 |
| Yacht Club Games | 2011 | 3 | 3 |
| Zachtronics | 2011 | 6 | 6 |
| ZeniMax Media | May 26, 1999 | — | 1 |
| ZeniMax Online Studios | 2007 | 1 | — |
| Ziggurat Interactive | — | — | 36 |
| Zing Games | 2011 | 1 | — |
| Zipper Interactive | 1995 | 9 | — |
| Zombie Studios | 1994 | 6 | — |
| Zono | 1991 | 2 | — |
| Zoo Publishing | 2001 | — | 2 |
| Zynga | 2007 | 3 | 2 |