| qtmp | Qtracker Mapshot Pack |
| qtpp | Qtracker Update Data |
| qtr | Vectorworks v11 Workspace |
| qtsx | QuickTapSurvey Data |
| qtt | Qtracker Application Theme Data |
| qtx | QuaSZ Texture |
| qtx | QuickTime Extension |
| qtxs | QuickTime Data |
| qtxt | QuickShow Text Data |
| qu2 | GPS2WorldWind Data |
| quad | Geomview Quadrilaterals Data |
| qual | Quality Score File |
| que | CuteFTP Queue Data |
| query | Microsoft PCHealth Query File |
| qui | Orgadata LogiKal Data |
| quickendata | Intuit Quicken Essentials for Mac Data |
| quiz | Question Object File Format |
| quo | eSignal Quote Data |
| quox | Question Object File Format |
| qut | IBM Voice Type Languages Vocables Data |
| qvb | MultiWell Thermo Vibrations Data |
| qvc | QlikView Component |
| qvm | Q Virtual Machine |
| qvo | QlikView Table Data |
| qvt | QlikView Theme |
| qvx | QlikView Data eXchange File |
| qw | QmailAdmin Data |
| qwb | Microsoft Money Data |
| qwk | QWK Offline Mail Packet |
| qwmod | Intuit Quicken for Windows Module Data |
| qwp | Quiptics Cryptogram |
| qwpx | Quiptics Cryptogram |
| qws | Qt Workspace Data |
| qwz | Question Writer File |
| qxdm | Qualcomm eXtensible Diagnostic Monitor Log |