| Whanau Day Nursery (ST Albans) LLP | | 2011 |
| Wharton Family Holdings Limited | Professional & scientific | 2000 |
| What Else Property Limited | Financial services | 2023 |
| What the Duck Productions Ltd | Information & communication | 2022 |
| Wheathampstead Cricket Club Limited | Financial services | 2025 |
| Wheathampstead Food Ltd | Hospitality | 2017 |
| Wheathampstead Golf Village Limited | Wholesale & retail | 2024 |
| Wheathampstead Land Company Limited | Construction | 1995 |
| Wheathampstead Warriors Limited | Arts & recreation | 2018 |
| Wheely Good Ceramics Ltd | Manufacturing | 2026 |
| When YOU Were Young S&E Ltd | Professional & scientific | 2023 |
| White Bench Ltd | Real estate | 2026 |
| White Fang Films Limited | Information & communication | 2005 |
| White Moon Limited | Information & communication | 2012 |
| White Orthodontics Limited | Health & social care | 2012 |
| Whiteday Limited | Real estate | 2017 |
| Whites ST. Albans Limited | Transport & logistics | 2010 |
| Whitewalls Property Limited | Construction | 2025 |
| Whitford and Hughes Limited | Extraterritorial | 1989 |
| WHY Projects Limited | Professional & scientific | 2012 |
| Wild Card League Ltd | Professional & scientific | 2026 |
| Wild Horses Group Ltd | Hospitality | 2026 |
| Wild IVY Events Ltd | Administrative & support | 2023 |
| Wild Oak Estates Limited | Real estate | 2012 |
| Wild Rice Films Ltd | Information & communication | 2019 |
| Wildlife Conservation Projects Limited | Administrative & support | 2021 |
| Wildside Outdoors Limited | Education | 2018 |
| William Alex Limited | Administrative & support | 2019 |
| William Bowman Construction Limited | Real estate | 2015 |
| William Bowman Consulting Limited | Financial services | 2017 |
| William Bowman Homes Limited | Real estate | 2015 |
| William Bowman Investments Limited | Real estate | 2012 |
| William James Management Services Ltd | Professional & scientific | 2024 |
| William Lawrence Advertising Limited | Professional & scientific | 1985 |
| William Scott Associates Limited | Administrative & support | 2009 |
| Williams Motor Cars Ltd | Wholesale & retail | 2025 |
| Willow & YEW Ltd | Manufacturing | 2018 |
| Willow and Bloom Limited | Administrative & support | 2019 |
| Willow Management(Uk) Limited | Real estate | 2009 |
| Willows Electrical Services Ltd | Construction | 2023 |
| Willows Farm Day Nursery Limited | Education | 2012 |
| Willway Legacy Ltd | Financial services | 2017 |
| Willwriting and Estate Planning Limited | Professional & scientific | 2009 |
| Wilson Sports Events Architecture Limited | Professional & scientific | 2021 |
| Wilstom Limited | Administrative & support | 2010 |
| Wima Assets Limited | Real estate | 2026 |
| Winchfield Caddington Management Company Limited | Households | 2001 |
| Wind Field One Limited | Energy | 2024 |
| Windfall Accounting LLP | | 2019 |
| Windfall Logistics Limited | Wholesale & retail | 2007 |
| Window Wise Trade Limited | Construction | 1998 |
| Winfinity Events Ltd | Other services | 2019 |
| Wing Cars Limited | Transport & logistics | 2013 |
| Winguard Property Limited | Real estate | 2024 |
| Winnies Catering Limited | Administrative & support | 2016 |
| Winova Property Investments Limited | Real estate | 2017 |
| Winova Property Refurbishments Limited | Administrative & support | 2017 |
| Winova Property Sourcing Limited | Real estate | 2018 |
| Winova Property Trading Limited | Real estate | 2018 |
| Winser Futures Limited | Financial services | 1994 |
| Winstars Technology Limited | Wholesale & retail | 2025 |
| Winward Holdings Limited | Financial services | 2021 |
| Wirefast Limited | Information & communication | 1999 |
| Wiseman Opticians (Hampstead) Limited | Wholesale & retail | 1977 |
| Wiser Group Limited | Professional & scientific | 2016 |
| Wizard Staff Solutions Ltd | Administrative & support | 2015 |
| Wizard Tabeze Ltd | Administrative & support | 2020 |
| WKD Distribution Limited | Wholesale & retail | 2011 |
| WMD Property Management Ltd | Real estate | 2015 |
| WME Management Solutions Ltd | Professional & scientific | 2017 |
| Wolden Garden Centre Limited | Agriculture & fishing | 2008 |
| Wolf & Stone Ltd | Arts & recreation | 2011 |
| Wolf&Co Limited | Other services | 2025 |
| Wolfe Psychology Limited | Education | 2016 |
| WON Restaurant Limited | Hospitality | 2024 |
| Wonder Village LLP | | 2026 |
| Wood Hall Projects Limited | Administrative & support | 2016 |
| Woodblock Properties Limited | Real estate | 2020 |
| Woodcloud Ltd | Professional & scientific | 2025 |
| Woodland Consultancy Services Limited | Administrative & support | 1982 |
| Woodlands Home Nursery Limited | Education | 2015 |
| Woodpath Ltd | Professional & scientific | 2025 |
| Woodstock Cable Ltd | Information & communication | 2025 |
| Woolf’S Pack Ltd | Other services | 2026 |
| Woolliscroft's Limited | Real estate | 1905 |
| Woolmer Service Station Limited | Wholesale & retail | 1988 |
| Wooster Jeffs Associates Ltd | Professional & scientific | 1997 |
| Wordsmith Creative Studio Ltd | Arts & recreation | 2017 |
| Work Stories Coaching Ltd | Professional & scientific | 2024 |
| Work Well Physiotherapy Ltd | Health & social care | 2023 |
| Workfinder Limited | Administrative & support | 2019 |
| Workforce 24 Hours Ltd | Administrative & support | 2018 |
| Workforce Engineering Services Limited | Administrative & support | 2013 |
| Workshop Labs UK PBC Ltd | Information & communication | 2025 |
| World of Waffle Wands Limited | Financial services | 2025 |
| World of Whisky Group Limited | Wholesale & retail | 2023 |
| World of Whisky Group Wholesale Limited | Wholesale & retail | 2025 |
| Worldbeatsmusic Ltd | Education | 2010 |
| Worldwide Hole'N One Limited | Financial services | 1995 |
| WORLDX35 Ltd | Financial services | 2014 |