| White Horse Capital | |
| White Label Crowdfunding | West Yorkshire |
| White Label Solutions | |
| White Rabbit Consultancy | |
| White Rose Software | West Yorkshire |
| White Space Advertising Ltd | |
| White Star Capital | |
| White Status | Leicestershire |
| Whiteboardmaths.com | Lincolnshire |
| Whitedog | Staffordshire |
| Whitefish Marketing Ltd | |
| Whitehall Media Ltd | |
| Whitehouse Communications | |
| Whiteland Engineering Ltd | |
| WhiteNoise Media | |
| Whiteoaks International | |
| Whitesmith | |
| Whitespace | |
| Whitespider | |
| Whitewall | |
| Whiz Solutions Ltd | Greater London |
| WHMCS Ltd | Buckinghamshire |
| WhoisTrustee.com Ltd | |
| Wholegrain Digital | |
| WholeLot | |
| WholesGame | |
| WhoopIt | |
| WhosOn | Staffordshire |
| WHP Creative | |
| WHP Telecoms Ltd | Cheshire |
| WHR Marketing Ltd | |
| Why Media | |
| Why Research Ltd | |
| Why Think Domains Ltd | Surrey |
| WhySettle | |
| Wi-Manx Ltd | Isle of Man |
| Wibble Web Design Ltd | Belfast |
| WICASTR | |
| Wicked Kippers | |
| Wickham Micro Ltd | |
| Wickham Micro Ltd | |
| Wicks and Wilson | Hampshire |
| Wida Group Ltd | Nottinghamshire |
| Wide Angle Software | Wiltshire |
| Wide Network Solutions Ltd | |
| Wideopenspace Ltd | |
| Widescope.net | Northumberland |
| Widgit Software | Warwickshire |
| Wieser Software | Cambridgeshire |
| WiFiGear Ltd | |