| UDP | User Datagram Protocol |
| UI | User Interface |
| UIDL | Unique ID Listing |
| UNC | Universal (Uniform) Naming Convention |
| URL | Uniform Resource Locator |
| USNO | United States Naval Observatory |
| UT | Universal Time |
| UTC | Coordinated Universal Time |
| UUID | Universally Unique Identifier |
| VAR | Value-Added Resellers |
| VDD | Virtual Device Driver |
| VDM | Virtual MS-DOS Machine |
| VESA | Video Electronics Standards Association |
| VME | Virtual Module European |
| VPN | Virtual Private Network |
| VRML | Virtual Reality Modelling Language |
| W3C | World Wide Web Consortium |
| WAIS | Wide Area Information System |
| WAN | Wide Area Network |
| WINS | Windows Internet Name System (Windows NT) |
| WWW | World Wide Web |
| WYSIWYG | What You See Is What You Get |
| XBM | X-Windows BitMap |
| YNLR | Yo Nunca Las Recuerdo |