| Astralore | Developer | |
| Astrid Dalmady | Developer | |
| Astridelta | Developer | |
| Astro | Developer | |
| Astro Lords Dev | Developer | |
| Astro Port | Developer | |
| Astro1 | Developer | |
| AstroBearGames | Developer | |
| AstroLabe | Developer | |
| AstroSocks | Developer | |
| Astrogun | Developer | |
| Astroillogica | Developer | |
| Astrojone | Developer | |
| Astroll | DeveloperPublisher | |
| AstrollJP | Publisher | |
| Astronation | Developer | |
| Astronaut Curve | Developer | |
| Astronauts | DeveloperPublisher | |
| Astronautz | Developer | |
| Astrophobia | Developer | |
| Astros Productions | DeveloperPublisher | |
| Astros Productions (Peter Karboulonis, George Karboulonis) | Developer | |
| Astrosaurus Games | DeveloperPublisher | |
| Astrovision | Developer | |
| Astucia | Developer | |
| Astus Games | Developer | |
| AstuteOne | Developer | |
| Asue | Developer | |
| Asuka Technologies | Developer | |
| Asuro | Developer | |
| Asylum Entertainment | DeveloperPublisher | |
| Asylum Square | Developer | |
| Asylum Square Interactive | Publisher | |
| Asylum studios | Developer | |
| AsylumSquad | Developer | |
| Asymetrical Pigeon | Developer | |
| Asymmetric Publications | DeveloperPublisher | |
| Asynchron | Developer | |
| AtKombi | Developer | |
| Ata Dogan | Developer | |
| Atapki | Developer | |
| Atara Gracia | Developer | |
| Atari | DeveloperPublisher | |
| Atari (Infogrames) | Publisher | |
| Atari (Infrogames) | Publisher | |
| Atari (NA) | Publisher | |
| Atari (Overseas) | Publisher | |
| Atari 2600 Land | Publisher | |
| Atari Corp. | Publisher | |
| Atari Corporation | DeveloperPublisher | |
| 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 | |