| AccoladeNA | Publisher | |
| AccoladePAL | Publisher | |
| According to Prophecy | Developer | |
| Accursed Toys | Developer | |
| Ace Maddox | DeveloperPublisher | |
| Ace Savaid | Developer | |
| Ace Software (Alan Cresswell) | Developer | |
| Ace Software (Alan P. Cresswell) | Developer | |
| Ace Team | Developer | |
| Ace of Wands | Developer | |
| AceMark | Developer | |
| AceOfAces | Developer | |
| Acemoisan | Developer | |
| Acer | Publisher | |
| Aces Games | Developer | |
| Achie | Developer | |
| Achromateam | Developer | |
| Acid | Developer | |
| Acid Nerve | Developer | |
| Acid Plan | DeveloperPublisher | |
| Acid Software | DeveloperPublisher | |
| Acid Wizard Studio | Developer | |
| Acid x Kitty | Developer | |
| AcidSpaceshipp | Developer | |
| AcidicDuck | Developer | |
| AcidosisProductions | Developer | |
| Ackk Studios | DeveloperPublisher | |
| Aclips | Developer | |
| Acme Animation | DeveloperPublisher | |
| Acme Interactive | Developer | |
| Acme Interactive Productions | Developer | |
| Acme Nerd Games | Developer | |
| Aconitum Games | Developer | |
| Acony | Developer | |
| Acorn Software | Publisher | |
| Acquire | DeveloperPublisher | |
| Acquire Corp | Publisher | |
| AcroPR | Developer | |
| Acropolise | Developer | |
| Acrosicious | Developer | |
| Acroviu | Developer | |
| Act Japan | Developer | |
| Actainment | Developer | |
| Actawesome | Developer | |
| Acti-Art | DeveloperPublisher | |
| Action 53 | Developer | |
| Action Button | Developer | |
| Action Forms | Developer | |
| Action Graphics | Developer | |
| Action Software | Publisher | |
| Action Software (Oscar Gallego Sendin, Ignacio Mendez, Javier Fafula) | Developer | |
| ActionMan | Developer | |
| Actioncraft | Publisher | |
| Actionsoft | DeveloperPublisher | |
| Active | Developer | |
| Active Gaming Media | DeveloperPublisher | |
| Active Magic (Davor Magdic) | Developer | |
| Active Magic (Predrag Beciric, Aleksandar Petrovic, Vojislav Mihailovic, Predrag Milicevic) | Developer | |
| Active Minds (John Pickford, Mark R. Jones, Simon Butler, David Whittaker) | Developer | |
| Active Software | DeveloperPublisher | |
| ActiveUP Games | Developer | |
| Activision | DeveloperPublisher | |
| Activision 02 | Publisher | |
| Activision Blizzard | Publisher | |
| Activision EU | Publisher | |
| Activision EU/NA | Publisher | |
| Activision NA | Publisher | |
| Activision NA/EU | Publisher | |
| Activision O2 | Publisher | |
| Activision Publishing | Publisher | |
| Activision Publishing, Inc. | DeveloperPublisher | |
| Activision Value | DeveloperPublisher | |
| Activision Value Publishing | Publisher | |
| Activision Value Publishing, Inc. | Publisher | |
| Activision ValueAU | Publisher | |
| Activision, | Publisher | |
| ActivisionAU | Publisher | |
| ActivisionEU | Publisher | |
| ActivisionEU,NA | Publisher | |
| ActivisionJP | Publisher | |
| ActivisionJP,PAL | Publisher | |
| ActivisionNA | Publisher | |
| ActivisionNA, PAL | Publisher | |
| ActivisionNA,PAL | Publisher | |
| ActivisionPAL | Publisher | |
| ActivisionPAL,NA | Publisher | |
| Activison | Developer | |
| Actoon Studio | DeveloperPublisher | |
| Actos Games | DeveloperPublisher | |
| Actoz Soft | DeveloperPublisher | |
| Acttil | DeveloperPublisher | |
| Actual Humans | Developer | |
| Actualize | Publisher | |
| Actually The Moon | Developer | |
| Actura Software | DeveloperPublisher | |
| Acumen Software | Publisher | |
| Ada Interactive | Developer | |
| Ada Rook | Developer | |
| Adafheyesh | Developer | |
| Adagio Games | Developer | |