| HotGen | United Kingdom | 1999 | 4 | 2 |
| Hothead Games | Canada | 2006 | 1 | 1 |
| Hothouse Creations | United Kingdom | 1996 | 1 | — |
| Houghton Mifflin Harcourt | United States | 1880 | — | 1 |
| Hound Picked Games | United Kingdom | June 22, 2018 | — | 1 |
| Hudson Soft | Japan | May 18, 1973 | 102 | 97 |
| Human Entertainment | Japan | 1983 | 23 | 12 |
| Human Head Studios | United States | October 1997 | 2 | — |
| HumaNature Studios | United States | — | 1 | — |
| HumanSoft | United States | 1994 | 2 | — |
| Humble Bundle, Inc. | United States | March 2010 | — | 6 |
| Humble Games | United States | — | — | 26 |
| Humble Grove | United Kingdom | — | 1 | — |
| Hummer Team | Taiwan | 1992 | 3 | — |
| Hummingbird Soft | Japan | 1982 | 2 | — |
| HummingBirdSoft | Japan | 1982 | 5 | 3 |
| Humongous Entertainment | Russia | October 30, 1992 | 37 | 7 |
| HuneX | Japan | October 1992 | 20 | 2 |
| Hungry Bear Games | Brazil | — | 1 | — |
| Hunted Cow Studios | United Kingdom | — | 1 | — |
| Hutch Games | United Kingdom | July 4, 2011 | 1 | 1 |
| Hyde | Japan | August 2002 | 3 | — |
| Hydra Games | Poland | — | 1 | 1 |
| HyperBeard | Mexico | — | 1 | 3 |
| HyperGryph | People's Republic of China | January 24, 2017 | 2 | 2 |
| Hyperstrange | Poland | 2015 | 3 | 5 |
| HypeTrain Digital | Cyprus | — | 1 | 19 |
| Hypnotix | United States | 1993 | 1 | — |
| 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 |