| mode | Coda Syntax Mode |
| model | CATIA Model Data |
| model | Ribbons Model Definition |
| modfem | Femap Model File |
| modus | Adobe Mocha for After Effects Modus Data |
| moe | Molecular Operating Environment File |
| moef | Motion Effect Template |
| mogrt | Adobe Premiere Motion Graphics Template |
| mohobrush | Moho Brush Data |
| mohostyle | Moho Style Data |
| mojito | LimeWire Kademlia Data |
| mol | MDL Molfile Data |
| mol | Music Module List |
| mol2 | Tripos Mol2 Format File |
| molo | Motion Object |
| mologiq | HTC EVO 3D Data |
| mon | Steinberg WaveLab Audio Montage |
| mon2 | UltraSite Graphical Status Data |
| monet | Adobe Mocha for After Effects Monet Data |
| moneywell | MoneyWell Account Data |
| mongodb | MongoDB Database |
| mono | Monolith Munged Encoded Data |
| monte | CRiSP Monte Carlo Method Data |
| mood | Amarok Moodbar Data |
| mop | MOPAC Input Format Data |
| mopcrt | MOPAC Cartesian Data |
| mopint | MOPAC Internal Data |
| mopout | MOPAC Chemical Output Data |
| mopp | Havok Engine MOPP Data |
| mor | Poser 3D Morph Target |
| morg | Morg Data |
| mos | ENVI Mosaic Data |
| mot | Animation Master Motion Data |
| mot | MarcEdit Template |
| moti | Motion Title Template |
