| W | Ashton Tate Applause Chart |
| W | Progress Database File |
| W30 | Ventura Printer Font |
| W31 | Windows 3.1 Startup File |
| W3D | Black Belt Systems Ray Trace Control File |
| W40 | Win95 Backup File |
| W44 | dBase Temporary File |
| W51 | WordPerfect 5.1 Document |
| WAB | MS Outlook Address Book |
| WAD | Programming Library |
| WAD | Game File (various games) |
| WAL | Quake 2 Texture File |
| WAL | WalMaster Showlist File |
| WAR | Java Web Archive |
| WAS | Procomm Plus Script Source Code File |
| WAV | Waveform Audio |
| WAX | Procomm Plus Compiled Script File |
| WAX | Metafile |
| WB | Dictionary Project Data File |
| WB1 | QuattroPro for Windows Spreadsheet |
| WB2 | QuattroPro for Windows Spreadsheet |
| WB2 | Lotus 1-2-3 for OS/2 Spreadsheet |
| WB3 | QuattroPro for Windows Spreadsheet |
| WBC | Webshots Picture Collection |
| WBD | Webshots Graphic Format |
| WBF | Windows Batch File |
| WBK | WordPerfect Workbook Document |
| WBK | Microsoft Word Backup |
| WBL | Argo WebLoad II Upload File |
| WBR | Crick Software WordBar File |
| WBS | WebExpress Website File |
| WBS | Webshots Screensaver |
| WBT | Crick Software Wordbar Template |
| WBT | WinBatch Script |
| WBZ | WebShots File |
| WCD | WordPerfect Macro Token List |
| WCH | Corel Office PerfectScript |
| WCI | Catalog File Maintained by MS Indexing Service |
| WCM | Microsoft Works Communications Terminal |
| WCM | WordPerfect Macro |
| WCM | Corel Presentations Macro |
| WCP | WordPerfect Product Info |
| WD2 | WordExpress Document |
| WDB | Microsoft Works Database |
| WDD | Wright Design Image |
| WDF | Sourcer Disassembler by V Communications |
| WDK | WhizFolder Desktop File |
| WDL | Windows XP Watchdog Log File |
| WEB | Corel Xara Web Document |
| WEB | Web Vector Graphic File |
| WFA | WinFax Pro Archive |
| WFB | Turtle Beach WaveFront Bank |
| WFD | Turtle Beach WaveFront Drum Set |
| WFM | dBASE Form Designer |
| WFN | Corel Draw Vector Font |
| WFP | Turtle Beach WaveFront Program |
| WFS | Windows Installation Script |
| WFX | Winfax Data File |
| WG1 | Lotus 1-2-3/G Spreadsheet |
| WG2 | Lotus1-2-3 for OS/2 Spreadsheet |
| WGP | Wild Board Games Data File |
| WHT | Microsoft Net Meeting Whiteboard Document |
| WID | Ventura Width Table |
| WIF | Weaving Information Format |
| WIF | Wang Image File |
| WIF | Wavelet Image |
| WIL | WinImage File |
| WIL | Windows Interface Language Script |
| WIN | dBase or Foxpro Window |
| WIN | Windows Backup File |
| WIP | Windows Installer Project |
| WIZ | Microsoft Word or Publisher Wizard |
| WK! | Lotus Spreadsheet File |
| WK1 | Lotus 123 versions 1 & 2 Spreadsheet |
| WK3 | Lotus 123 version 3 Spreadsheet |
| WK4 | Lotus 123 version 4 Spreadsheet |
| WK5 | Lotus 123 version 5 Spreadsheet |
| WKB | WordPerfect Document |
| WKB | Workbook (various) |
| WKE | Lotus 1-2-3 Educational Version Spreadsheet |
| WKQ | Borland Quatro Spreadsheet |
| WKS | Lotus 123 Worksheet Spreadsheet |
| WKS | Microsoft Works Spreadsheet |
| WKS | XLISP Workspace |
| WKZ | Compressed Spreadsheet |
| WLD | Adobe Acrobat Distiller |
| WLF | Argo WebLoad I Upload File |
| WLG | Dr. Watson Log |
| WLK | Virtus Walk Through Image |
| WLL | Microsoft Word Add-In |
| WLL | The Sims (Maxis) Wall Texture File |
| WLR | VRML Page |