| Studio Thunderhorse | United States | — | 1 | — |
| Studio Wildcard | — | 2014 | 1 | 1 |
| Stunlock Studios | Sweden | 2010 | 2 | 1 |
| Sublogic | United States | 1977 | 4 | 3 |
| Success | Japan | 1978 | 14 | 11 |
| Sugar Games | Russia | 2003 | 1 | 1 |
| Summitsoft Entertainment | United States | May 3, 1993 | — | 1 |
| Sumo Digital | United Kingdom | 2003 | 16 | 1 |
| Sumo Nottingham | United Kingdom | 2016 | 1 | — |
| Sumzap | Japan | — | 1 | 1 |
| Sun Microsystems | United States | February 24, 1982 | — | — |
| Sunborn Network Technology | People's Republic of China | October 2015 | 1 | 1 |
| Suncrash | Israel | December 2014 | 1 | — |
| Sundae Factory | — | — | 1 | 1 |
| SunDust | — | — | — | 2 |
| Sunflowers Interactive Entertainment Software | Germany | 1993 | — | 4 |
| Sungrand Studios | Australia | — | 2 | 2 |
| Sunhead Games | Taiwan | March 2012 | 3 | — |
| Sunlight Games | Germany | — | 2 | 2 |
| Sunna Entertainment | Costa Rica | 2014 | 1 | — |
| Sunnyside Games | Switzerland | 2013 | 3 | — |
| Sunrise Interactive | Japan | 1998 | 2 | — |
| Sunscorched Studios | United Kingdom | April 11, 2019 | 2 | 1 |
| Sunsoft | Japan | 1978 | 17 | 26 |
| Sunstorm Interactive | United States | 1995 | 6 | — |
| Suntendy Interactive Multimedia Co.,Ltd. | People's Republic of China | June 2, 1997 | — | 31 |
| Super Evil Megacorp | United States | 2012 | 1 | 1 |
| Super PowerUp Games | Spain | — | 6 | 13 |
| Super Rare Games | United Kingdom | October 25, 2017 | — | 1 |
| Super X Studios | United States | 1998 | 2 | 1 |
| Supercell | Finland | May 14, 2011 | 2 | 2 |
| SuperGaming | India | 2017 | 1 | 1 |
| Supergiant Games | United States | 2009 | 1 | 1 |
| Supergonk | United Kingdom | — | 1 | 1 |
| Superior Software | United Kingdom | 1982 | — | 1 |
| Supernova Games Studios | Italy | 2021 | 1 | — |
| Superscape | United Kingdom | 1983 | 4 | — |
| Supersonic Software | United Kingdom | 1989 | 1 | — |
| SuperVillain Studios | United States | 2004 | 3 | 1 |
| Supra Games | Germany | — | 2 | 2 |
| SureAI | Germany | 2003 | 2 | 2 |
| Surreal Software | United States | 1995 | 4 | — |
| Survios | United States | 2013 | 5 | 4 |
| Suspicious Developments | United Kingdom | 2012 | 1 | 1 |
| Suzak Inc. | Japan | June 26, 2000 | 4 | — |
| Sveriges Radio | Sweden | February 6, 1991 | 1 | 1 |
| Sveriges Television | Sweden | 1978 | 1 | 10 |
| SVG Distribution | — | 1980 | 1 | — |
| SVT Drama | Sweden | 1996 | — | 1 |
| Swan | Japan | October 5, 1995 | 7 | 7 |
| Sweet Baby Inc. | Canada | 2018 | 1 | — |
| Sweet Bandits Studios | Canada | 2016 | 1 | — |
| Swiss Agency for Development and Cooperation | Switzerland | 1960 | — | 1 |
| Swiss Federal Institute of Technology in Lausanne | Switzerland | 1969 | — | 1 |
| Swisscom | Switzerland | October 1997 | — | 1 |
| Swisslos | Switzerland | 1937 | — | 1 |
| Swordfish Studios | United Kingdom | 2002 | 1 | — |
| SwordSwipe Studios | United States | — | 1 | — |
| SYBO Games | Denmark | 2010 | 1 | 1 |
| Syn Sophia | Japan | 1995 | 15 | — |
| Synapse Software | United States | 1981 | 1 | — |
| Synergistic Software | United States | 1978 | 2 | 1 |
| Synetic GmbH | Germany | 1996 | 1 | — |
| System 3 | United Kingdom | 1984 | 6 | 4 |
| System Sacom | Japan | 1981 | 4 | 1 |
| SystemSoft | Japan | September 28, 1979 | 1 | 1 |
| SystemSoft Alpha | Japan | April 1999 | 1 | 7 |
| T-ARTS | Japan | February 9, 1988 | — | 2 |
| T-Bull | Poland | 2010 | 1 | 1 |
| T-Time Technology | Taiwan | April 11, 1992 | — | — |
| Tactics | Japan | 1997 | 1 | — |
| Tactile Games | Denmark | 2009 | 1 | 1 |
| Tag Games | United Kingdom | 2006 | 2 | — |
| Taito | Japan | August 24, 1953 | 61 | 86 |
| Takara | Japan | September 17, 1955 | 3 | 24 |
| Take Two Interactive GmbH | Germany | — | — | 2 |
| Take-Two Interactive | United States | 1993 | 1 | 25 |
| Take-Two Licensing | United States | 2004 | — | 2 |
| Takeru | Japan | — | 1 | 1 |
| Takumi Corporation | Japan | 1994 | 4 | — |
| Takuyo | Japan | February 1991 | 7 | 7 |
| TaleWorlds | Turkey | 2005 | 4 | 2 |
| TallBoys | Russia | — | 1 | 1 |
| TalonSoft | United States | 1995 | — | 1 |
| Tamsoft | Japan | June 26, 1992 | 35 | — |
| Tandem Verlag | Germany | 1994 | — | — |
| Tandy Corporation | United States | 1919 | — | 1 |
| Tango Gameworks | Japan | March 2010 | 4 | — |
| Tantalus Media | Australia | 1994 | 12 | — |
| Tanuki Game Studio | Spain | 2011 | 1 | — |
| Tapulous | United States | 2008 | 4 | — |
| Targem Games | Russia | 2002 | 3 | — |
| Target Games | Sweden | 1980 | 2 | — |
| Tarsier Studios | Sweden | 2004 | 2 | 1 |
| Tasto Alpha | Japan | June 3, 2019 | 1 | — |
| Tasuke | Japan | February 2002 | 1 | 1 |
| Tate Multimedia | Poland | 2000 | 5 | 2 |
| TATI Mixedia | Sweden | 1991 | 3 | — |
| TATSUJIN | Japan | May 2017 | 2 | 1 |
| Tatsumi | Japan | August 25, 1970 | 1 | 1 |