| 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 | |