| qrz | QF-Test Compressed Run Log |
| qs | QSplat Model |
| qsc | KaleidaGraph Script |
| qsd | Quicken Data |
| qsdat | QuickShow Data |
| qsed | QvodPlayer Data |
| qseg | SlimBrowser Engine Definition Data |
| qsession | AB SCIEX MultiQuant Quantitation Session Data |
| qsf | Qualtrics Survey Data |
| qsf | Quintessential Player Family Skin |
| qsfl | Symantec Antivirus Check Data |
| qsi | QTL Simulation Information File |
| qsk | Quintessential Player Kid Skin |
| qsm | QuickBooks Statement Writer Statement Data |
| qsn | TapCIS QuickScan Data |
| qsr | CARE-S Water Quality Simulation Results Data |
| qst | Intuit Quicken v4 Data File |
| qst | KaleidaGraph Style |
| qstx | Quest III Quote File |
| qsty | KaleidaGraph Style |
| qsw | QuickShow Workspace Data |
| qsx | QuickSurf Data |
| qt2 | ViewChoice QT2 Data |
| qt3d | QT 3D Data |
| qtb | ExamView Question Bank Data |
| qtch | QuickTime Player Cache |
| qtf | Qtracker Filter |
| qtg | QTgrader Data |
| qth | WinOrbit Observer Database |
| qtindex | Adobe Premiere QTIndex |
| qtindex | Adobe Premiere QuickTime Index |
| qtm | Quanquest Quantum Element Definitions Data |
| qtmp | Qtracker Mapshot Pack |
| qtpp | Qtracker Update Data |
| qtr | Vectorworks v11 Workspace |