| tvvi | TitanTV Television Program Data |
| tvx | Lucene Term Vector Index |
| tw0 | Native Instruments B4 II Tonewheel Data |
| twb | Tableau Workbook |
| twbx | Tableau Packaged Workbook |
| twf | Tecgraf Web Format |
| twf | TabWorks Data File |
| twg | CARE-S InfoWorks Trade Waste Data |
| twi | SDDS Toolkit Data |
| twk | T-Works Manager Data |
| twm | TheWord Module |
| twrp | TWRP Data |
| tws | TextPad Workspace |
| tww | Tagwrite Template |
| twz | theWord Compressed Archive Module |
| twzip | theWord Compressed Archive Module |
| tx | TX Text Control Data |
| tx0 | Portable Radiation Package Data |
| tx1 | TracerX Log File |
| tx3 | Oasis Lite Gazetteer File |
| txa | Midas ViewPoint Text Array List |
| txa | PTC Creo Training File |
| txb | EES Textbook |
| txf | TurboTax Tax Exchange Format |
| txm | TrakAxPC Mix File |
| txn | MySpaceIM Conversation Log |
| txn | SAP POS TXN Log File |
| txp | TerraPage Data |
| txtdt | DVD TEXT Data File |
| txtrpt | CommScope Teletilt Control System Text Site Report File |
| txtsrc | eMule Source Data |
| txv | RapidReader TextVision Data |
| txx | DataPerfect Text Storage |
| tx_ | Compressed TXT File |
| tym | Adobe Pagemaker Timestamp Data |