| Atari Europe | Publisher | |
| Atari Europe S.A.S.U. | Publisher | |
| Atari Games | DeveloperPublisher | |
| Atari Hunt Valley | Developer | |
| Atari Interactive | Publisher | |
| Atari NA | Publisher | |
| Atari SA | Publisher | |
| Atari, Inc. | DeveloperPublisher | |
| Atari, Inc.KO,NA,PAL | Publisher | |
| AtariAU | Publisher | |
| AtariAU,NA | Publisher | |
| AtariAge | Publisher | |
| AtariEU | Publisher | |
| AtariKafa | Developer | |
| AtariNA | Publisher | |
| AtariNA,PAL | Publisher | |
| AtariPAL | Publisher | |
| Atarisoft | DeveloperPublisher | |
| Ataro | Publisher | |
| Atelier Double | Developer | |
| Atelier Garbage | Developer | |
| Atelier Mimina | Developer | |
| Atelier Sentô | Developer | |
| Atelier-Sai | DeveloperPublisher | |
| Ateliér Duchů | Developer | |
| Atemly Games | Developer | |
| Atent Games | Publisher | |
| Atezai | Developer | |
| Athakaspen | Developer | |
| Athena | DeveloperPublisher | |
| Athena Co. | Publisher | |
| Athena Hollow | Developer | |
| Athena JP | Publisher | |
| AthenaJP | Publisher | |
| AthenaParadigm | Developer | |
| Athletic Design AB | Developer | |
| Aticora_Games | Developer | |
| Atium Addict | Developer | |
| Atiya Nova | Developer | |
| Atlach | Developer | |
| Atlantean Interactive | Publisher | |
| Atlantean Interactive Games | Publisher | |
| Atlantis Interactive Entertainment | Developer | |
| Atlantis Software | Publisher | |
| AtlasAndCo | Developer | |
| AtlasDev | Developer | |
| Atlingworth | Developer | |
| Atlus | DeveloperPublisher | |
| Atlus (NA) | Publisher | |
| Atlus Co. | DeveloperPublisher | |
| Atlus JP | Publisher | |
| Atlus NA | Publisher | |
| Atlus Persona Team | Developer | |
| Atlus USA | Publisher | |
| Atlus USANA | Publisher | |
| AtlusJP | Publisher | |
| AtlusJP,KO,NA | Publisher | |
| AtlusJP,KO.NA | Publisher | |
| AtlusJP,NA | Publisher | |
| AtlusNA | Publisher | |
| AtlusUS | Publisher | |
| Atlya | Developer | |
| Atma Weapon | Developer | |
| AtmaGame | Developer | |
| Atmark | DeveloperPublisher | |
| Atmos Games | Developer | |
| Atod | Developer | |
| Atod AB | Developer | |
| Atom Team | Developer | |
| AtomHack | Developer | |
| AtomLight | Developer | |
| Atomhead | Developer | |
| Atomic Blue | Developer | |
| Atomic Elbow | Developer | |
| Atomic Entertainment | Developer | |
| Atomic Fabrik Game Studio | Developer | |
| Atomic Games | DeveloperPublisher | |
| Atomic Kraken | Developer | |
| Atomic Motion | Developer | |
| Atomic Planet | Developer | |
| Atomic Planet Entertainment | Developer | |
| Atomic Revolution Software | Publisher | |
| Atomic Rocket Entertainment | Developer | |
| Atomic Toilet | Developer | |
| Atomic Wolf | Developer | |
| AtomicQ | Developer | |
| AtomicRaccoonFR | Developer | |
| Atomjack | Publisher | |
| Atooi | DeveloperPublisher | |
| Atozi | Developer | |
| Atrax | Developer | |
| Atrease | Developer | |
| Atreid Concept SA | Developer | |
| Atreyu | Developer | |
| Atrium601 | Developer | |
| Atrum | Developer | |
| Ats | Developer | |
| Atsina Corrington | Developer | |
| AttaBoy | Developer | |
| AttainableEnt | Developer | |
| Atte Okkonen | Developer | |
| Attention to Detail | Developer | |
| Atthiyya Ath | Developer | |
| Attic Door Productions | Developer | |
| Attic Entertainment Software | DeveloperPublisher | |
| AtticBoxGames | Developer | |
| Attica | Publisher | |
| Attica Kish | Developer | |
| AtticusFinn | Developer | |
| Attila Kertesz | Developer | |
| Attractive Games | Developer | |
| Attu Games | DeveloperPublisher | |
| Atty | Developer | |
| Atypical Alchemists Associate | DeveloperPublisher | |
| Atypical Games | DeveloperPublisher | |
| Atzi_ Games | Developer | |
| Aubry | Developer | |
| Audacity Interactive | DeveloperPublisher | |
| Audilis | Developer | |
| Audio Games | Developer | |
| Audio Visual Magic | Developer | |
| Audio Visual Magic (Gavin Wade, Chris Edwards) | Developer | |
| Audiogenic | DeveloperPublisher | |
| Audiogenic Software | DeveloperPublisher | |
| Audiosurf, LLC | Publisher | |
| Audiovisual Enterprises SA | Publisher | |
| Audre | Developer | |
| Audrey Castillo | Developer | |
| AudreyC | Developer | |
| AudreyL | Developer | |
| AudricGreenwood | Developer | |
| Auer | Developer | |
| AugEx | Developer | |
| AuggoFacts | Developer | |
| AugmentMyLife | Developer | |
| Augmented Irreality | Developer | |
| AugoGames | Developer | |
| Augur Studios | Developer | |
| AugureTeam | Developer | |
| August | DeveloperPublisher | |
| August Hemback | Developer | |
| August Håkansson | Developer | |
| Augustin Janvier | Developer | |
| Auhiro | Developer | |
| AukaneMin | Developer | |
| AukioGames | Publisher | |
| Aukustus | Developer | |
| Aula Arcade | Developer | |
| Aulas demonstrativas | Developer | |
| Aulden Carter | Developer | |