| qsl | Qedit Script |
| qss | QT Style Sheet |
| qsys | Intel Qsys System Data |
| qt7 | SAS 7 Sequential Engine Audit Data |
| qtd | Qt Creator Trace Data |
| que | PDP-10 Queue Data |
| qv7 | SAS 7 Sequential Engine View Data |
| qvs | QlikView Script |
| qx | Quex Input File |
| qx | Quexal Source Code |
| qxm | Quexal Macro File |
| r | Pegasus Mail Resource File |
| r | R Source Code |
| r | REBOL Source Code |
| r43 | IAR System MSP430 Object Module |
| radius | Ruby-Radius Script |
| rake | Rake File |
| rakefile | Ruby Makefile |
| raml | RESTful API Modeling Language Document |
| rap | RAPTOR Data |
| rapp | Ride7 Application |
| rb | RealBasic Source Code |
| rb | Ruby Console Application |
| rbc | Rembo-C Script Source |
| rbe | RealView Debugger Connection Properties |
| rbj | XRK Compiled Redcode Object File |
| rbm | RealBasic Menu |
| rbo | RealBasic Class |
| rbw | Ruby Windowed Application |
| rbx | Rembo-C Compiled Executable |
