| MachineGames |
| Mad Catz |
| Mad Doc Software |
| MADia Entertainment |
| Magenta Software |
| Magnum Games |
| Majesco |
| Malfador |
| Mandragora Team |
| Marvelous AQL |
| Marvelous Entertainment |
| Mass Media |
| Massive Development |
| Master Creating |
| Mastertronic |
| MASTiFF |
| Matrix Games |
| Matrix Software |
| MAUS Software |
| Maxis |
| Media Molecule |
| Media Vision |
| Mekensleep |
| Mercury Steam |
| Merge Games |
| Meridian4 |
| Merscom |
| Metalhead Software |
| Metamorf Studios |
| Metanet Software |
| Metia Interactive |
| Metro3D |
| Metropolis |
| MGame |
| Micro Application |
| Microids |
| Microprose |
| Microsoft Game Studios |
| Microsoft Game Studios Japan |
| Mid Carolina Media |
| Midway |
| Midway Austin |
| Midway Chicago |
| Might and Delight |
| Milestone Studios |
| Million |
| Mimimi Productions |
| Minds Eye Productions |
| Mindscape |
| Mindware Studios |
| Mine Loader |
| Minority |
| Mirage Interactive |
| MiST Land |
| Mistwalker |
| Mithis |
| Mixmax |
| Mojang |
| Momentum AS |
| Mommy's Best Games |
