| woa | WebObjects Application |
| wod | WebObjects Declaration |
| woo | WebObjects Object |
| workspace | Code::Blocks Workspace |
| wpss | IBM WebSphere Portal Server Settings Data |
| 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 |
| wsi | Wise Package Studio Installer Package |
| wsil | Web Services Inspection Language Data |
| wsm | Wise Package Studio Merge Module |
| wsrc | WAIS Source File |
| wte | WinDev Report Template |
| wwn | WebDev Browser Procedures |
| wwt | WebDev Page Template |
| wxf | WinSQL Scheduled Task Script |
| wxi | WiX Include File |
| wxl | WiX Localization File |
| wxr | wxWidgets Resource Data |
| wxres | WinDev Automatic Test Results |
| wxs | WiX Source File |
| wxt | WinDev Automatic Test |
| x | Microsoft DirectX D3D Object |
| x | XBLite Source Code |
| xadl | XPLATFORM Application Program Definition |
| xal | Open XAL Configuration |
| xamlx | Visual Studio Workflow Service |
| xap | XACT Project File |
| xat | XAT Template |
| xbl | XBLite Source Code |
| xbml | SAP Business One Studio Workflow Process Data |
| xbw | SUP Hybrid Web Container Workflow |