| Winchester Web Works Ltd | |
| Winding Tree | |
| Windle Creative | |
| Windmill Software | Greater Manchester |
| Windrush Technology Ltd | Oxfordshire |
| Windsor Telecom plc | Surrey |
| Wing | |
| Wingpath Ltd | Hampshire |
| WinMan ERP | West Midlands |
| Winnersh Triangle Web Solutions Ltd | Devon |
| Winnow Solutions Ltd | |
| WinPure | Berkshire |
| Winserve | Bristol |
| Winslow Adaptics Ltd | Powys |
| WinSpice | Cambridgeshire |
| Wintermute Trading Ltd | |
| Winterwell Associates Ltd | Edinburgh |
| Winton Group Ltd | |
| Wired Media | Bristol |
| Wired Sussex | East Sussex |
| Wired UK | |
| Wired2Fire Ltd | Surrey |
| WiredVibe Ltd | |
| Wirefox | |
| WireITFree | Hampshire |
| Wireless CCTV Ltd | Greater Manchester |
| Wireless Federation | |
| Wireless Infrastructure Group | |
| Wireless Logic Ltd | Berkshire |
| Wireless Terminal Solutions | Greater London |
| Wirral Met College | |
| Wirtech Ltd | |
| Wisdom Works Group | |
| Wise Marketing | Greater London |
| Wise Owl Business Solutions Ltd | Derbyshire |
| Wiser Websites | |
| WiserWeb | |
| Wish Agency Ltd | |
| Wishew | |
| WiSS | Gwynedd |
| WiSS | |
| WIT Fitness | |
| With Intelligence | |
| With Juno Ltd | |
| Withinweb | |
| Wivro | |
| Wixhill | |
| Wizard IT | Greater London |
| Wizard Online Solutions Ltd | |
| Wizard Systems UK | Bristol |