| qtindex | Adobe Premiere QuickTime Index |
| qtm | Quanquest Quantum Element Definitions Data |
| qtmp | Qtracker Mapshot Pack |
| qtpp | Qtracker Update Data |
| qtr | Vectorworks v11 Workspace |
| qtsx | QuickTapSurvey Data |
| qtt | Qtracker Application Theme Data |
| qttabgroup | QTTabBar Group Data |
| qtx | Intuit Quicken 2002 Data |
| qtx | QuaSZ Texture |
| qtx | QuickTime Extension |
| qtxs | QuickTime Data |
| qtxt | QuickShow Text Data |
| qtz | QuaSZ Texture Data |
| qu2 | GPS2WorldWind Data |
| quad | Geomview Quadrilaterals Data |
| qual | Quality Score File |
| que | CuteFTP Queue Data |
| que | Sphinx Questionnaire Data |
| query | Microsoft PCHealth Query File |
| qui | Orgadata LogiKal Data |
| quickendata | Intuit Quicken Essentials for Mac Data |
| quiz | Articulate QuizMaker 13 Data |
| quiz | Question Object File Format |
| quiztemplate | Articulate Quizmaker Template |
| 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 |
