| whs | WinHex Script |
| widget | HybridJava Widget |
| wiki | Wikitext Source Code |
| win | Visual FoxPro Window File |
| winmd | Microsoft Windows Metadata |
| winsqlscript | WinSQL Script |
| wiq | Visual Studio Work Item Query |
| wis | Rocket wIntegrate Script |
| wixlib | WiX Library File |
| wixmsp | WiX XML Patch File |
| wixmst | WiX Transform File |
| wixobj | WiX Object File |
| wixout | WiX XML Output File |
| wixpdb | WiX Debug File |
| wixproj | WiX Toolset Project File |
| wkf | KF Webserver Script |
| wli | WL Intermediate Data |
| wlmi | WLM Intermediate Data |
| wln | Novell Localisation Workbench Workspace |
| wlog | WinDev Runtime Log |
| wmb | 3D Gamestudio Compiled Map |
| wmk | WebMake Documentation Source Code |
| wmls | WMLScript File |
| wmlsc | Compiled WMLScript |
| wo | WebObjects Object |
| woa | WebObjects Application |
| wod | WebObjects Declaration |
| woo | WebObjects Object |
| workspace | Code::Blocks Workspace |
| wrn | Eclipse WRN Data |
| wrx | Progress OpenEdge ActiveX Properties |
| wscript | Waf Wscript |
| wsct | WinDev Test Scenario |
| wsdd | Axis Web Service Deployment Descriptor |
| wse | Wise Package Studio Script |