| mxls | MaxL Encyrpted Script |
| mxml | Adobe Flex Markup Language |
| mxo | Max Macintosh External Object |
| myapp | Visual Studio Application XML |
| mz | Mezzo Source Code |
| mzb | MegaZeux Board Data |
| mzi | Mezzo Interface File |
| mzx | MegaZeux World |
| n | Neko Bytecode |
| nbc | Next Byte Codes Source Code |
| nbin | Compiled NASL Script |
| ncb | Visual Studio No Compile Browse File |
| ncl | NCAR Command Language File |
| ndb | ProWorx NXT Short Comment with Blocking |
| ndf | ProWorx NXT Short Comment File |
| ndll | Neko Dynamic Library |
| ndx | WinDev HyperFileSQL Index |
| ned | OMNeT++ Network Description |
| neko | Neko Source Code |
| nesl | NESL Source Code |
| nfm | Delphi .NET Form |
| nfx | NetObjects Fusion Components |
| ngi | NGI Package |
| ngo | Norton Guide Linker Object |
| nhs | NHibernate Settings File |
| ni | NetObjects Fusion Preview |
| nib | Apple Interface Builder Resources |
| nim | Nimrod Source Code |
| nim | Nim Source Code |
| nimble | Nimble Package Data |
| nir | AdminStudio Repackaging Wizard Output |
| nj | Nunjucks Template |
| njk | Nunjucks Template |
| njs | Nunjucks Template |
| nk | NUKE Script |