| I Got Games | Singapore | — | 3 | — |
| Iam8bit | United States | 2005 | — | 3 |
| IBA Group | Czech Republic | 2005 | 1 | 1 |
| IBM | United States | June 16, 1911 | — | 2 |
| IC Games | Brazil | — | 1 | — |
| Icarus Studios | United States | — | 2 | — |
| Ice-Pick Lodge | Russia | 2002 | 5 | 1 |
| Iceberg Interactive | Netherlands | 2009 | — | 21 |
| Iced Lizard Games | United States | — | 1 | 1 |
| Iceflake Studios | Finland | 2007 | 1 | — |
| Icetesy SPRL | Belgium | — | 1 | 1 |
| ICOM Simulations | United States | March 4, 1981 | 3 | — |
| Idea Factory | Japan | October 27, 1994 | 17 | 40 |
| Idea Factory International | United States | September 30, 2013 | 1 | 11 |
| Ideaworks Game Studio | United Kingdom | 1997 | 3 | — |
| Idigicon Limited | United Kingdom | 1980 | 1 | 3 |
| Iggymob | South Korea | — | 1 | — |
| IguanaBee | Chile | 2011 | 3 | — |
| Ikegami Tsushinki | Japan | February 21, 1948 | 1 | — |
| Iko | France | November 24, 2009 | 1 | — |
| ILCA | Japan | October 2010 | 5 | — |
| IllFonic | United States | 2007 | 2 | 2 |
| Illumix | United States | — | 1 | 1 |
| Illusion | Japan | April 21, 2001 | 14 | 11 |
| Illusion Labs | Sweden | 2007 | 1 | — |
| Illuvium Labs | United Arab Emirates | — | 3 | 3 |
| Illwinter Game Design | Sweden | September 27, 2001 | 8 | 5 |
| ILMxLAB | — | 2015 | 1 | — |
| Image & Form | Sweden | 1997 | 3 | 1 |
| Image Space Incorporated | United States | 1992 | 3 | — |
| Image Works | United Kingdom | 1988 | — | 4 |
| Imageepoch | Japan | June 9, 2005 | 9 | 2 |
| Imagic | United States | 1981 | 3 | 2 |
| Imagination Games | — | 1984 | 1 | 1 |
| Imagine Software | United Kingdom | 1982 | — | 1 |
| Imagineer | Japan | January 27, 1986 | 2 | 12 |
| Imagineering | United States | 1987 | 15 | — |
| ImaginEngine | United States | 1994 | 5 | — |
| Imangi Studios | United States | 2008 | 1 | 1 |
| IMel | Japan | May 27, 2011 | 1 | 3 |
| IMGN.PRO | Poland | — | — | 3 |
| Implausible Industries | Japan | 2013 | 1 | — |
| Impressions Games | United States | 1989 | 5 | 1 |
| Incinerator Studios | United States | 2005 | 3 | — |
| Incognito Entertainment | United States | May 1999 | 3 | — |
| Incredible Technologies | United States | 1985 | 1 | — |
| Incubator Games | — | 2009 | 2 | — |
| Independent Arts Software | Germany | 1990 | 8 | — |
| Indie Built | United States | 1983 | 12 | 3 |
| IndieArk | People's Republic of China | — | — | 2 |
| Indienova | People's Republic of China | 2013 | — | 7 |
| IndiePub | United States | 2007 | — | 6 |
| IndieRevo | United Kingdom | — | 1 | 1 |
| Indieszero | Japan | April 21, 1997 | 6 | — |
| Infini-Brain Inc. | Japan | March 2, 2000 | 1 | 2 |
| Infinite Dreams | Poland | 2006 | 8 | 4 |
| Infinite State Games | United Kingdom | July 17, 2013 | 1 | 1 |
| Infinity Plus Two | Australia | 1989 | 5 | — |
| Infinity Ward | United States | 2002 | 9 | — |
| Inflexion Games | Canada | — | 1 | 1 |
| Infocom | United States | June 22, 1979 | 6 | 4 |
| Infomedia | France | 1986 | 3 | — |
| Ingram Entertainment Holdings Inc. | United States | 1981 | — | — |
| Ini3 Digital | Thailand | 2004 | — | 1 |
| INiS | Japan | 1997 | 4 | — |
| Inkle | United Kingdom | November 2011 | 6 | 4 |
| Inland Productions | United States | — | 2 | — |
| InLogic Software | Slovakia | 2005 | 3 | 1 |
| Innerloop Studios | Norway | 1996 | 2 | — |
| InnoGames | Germany | 2007 | 2 | 2 |
| Insomniac Games | United States | February 28, 1994 | 24 | — |
| Institute of National Remembrance | Poland | 1998 | — | 1 |
| Intel | United States | July 18, 1968 | 2 | 1 |
| Intelligent Games | United Kingdom | 1988 | 5 | — |
| Intelligent Systems | Japan | December 1986 | 58 | — |
| INTENSE | Japan | July 2002 | 2 | — |
| Intense Limited | Japan | July 2002 | 1 | 1 |
| Interactive Data Visualization Inc. | — | 2000 | — | — |
| Interactive Magic | United States | 1994 | 1 | 4 |
| Interactive Television Entertainment | — | 1988 | 5 | 1 |
| Interchannel | Japan | 1987 | — | 5 |
| Intergalactic Development | United States | — | 3 | — |
| Interheart | Japan | 1992 | — | 1 |
| International Fencing Federation | — | November 29, 1913 | — | 1 |
| International Games System | Taiwan | October 1991 | 2 | 1 |
| Interplay Entertainment | United States | October 1983 | 17 | 49 |
| InterServ International Inc | Taiwan | April 18, 1989 | 1 | — |
| Interstel Corporation | United States | — | — | 1 |
| Inti Creates | Japan | May 8, 1996 | 29 | 12 |
| IntraCorp | United States | 1984 | — | 3 |
| Introversion Software | United Kingdom | 2001 | 1 | 1 |
| Invader Studios | Italy | July 2016 | 2 | — |
| Invictus Games | Hungary | 2000 | 7 | 2 |
| InXile entertainment | United States | 2002 | 7 | 5 |
| IOMO | — | 2000 | 1 | — |
| Ion Storm | United States | 1996 | 3 | — |
| IQ Media Nordic | Sweden | April 21, 1992 | — | 2 |
| Irem | Japan | 1974 | 24 | 22 |
| Iron Galaxy Studios | United States | 2008 | 8 | — |
| Iron Gate Studio | Sweden | April 2019 | 1 | — |
| Iron Lore Entertainment | United States | October 2000 | 2 | — |
| Ironclad Games | — | 2003 | 2 | — |
| Ironhide Game Studio | Uruguay | January 26, 2010 | 8 | 7 |
| Ironhide Ireland Limited | Ireland | October 28, 2020 | — | 1 |
| Ironwood Studios | United States | — | 1 | — |
| Irrational Games | United States | 1997 | 6 | — |
| ISCO | Japan | 1987 | 1 | — |
| Ishtar Games | France | August 2005 | 2 | 1 |
| Isto Inc. | Canada | January 19, 2018 | 1 | 1 |
| It Matters Games | Germany | — | 4 | — |
| IV Productions | Italy | — | — | 13 |
| Ivanoff Interactive | Denmark | 1996 | 18 | 10 |
| IWare Designs | United Kingdom | September 24, 2010 | 1 | 1 |
| IzanagiGames | Japan | — | 1 | 2 |