| Whites Wheathampstead Limited | Construction | 2012 |
| Whitespace Studio Limited | Arts & recreation | 2009 |
| Whitespace Yoga Limited | Financial services | 2021 |
| Whitestone Finance Ltd | Financial services | 2024 |
| Whitethorne Property Management Limited | Real estate | 2024 |
| Whittaker's Embroidery Limited | Manufacturing | 2002 |
| Whittlestone Ltd. | Real estate | 1994 |
| Whole KIT & Kaboodle Ltd | Administrative & support | 2019 |
| Wholesale Carriage Company Ltd | Wholesale & retail | 2016 |
| Wholistique Suite CIC | Education | 2025 |
| WHP Investment Properties Limited | Financial services | 2026 |
| Whytec Limited | Professional & scientific | 1990 |
| Whytes Holding Ltd | Information & communication | 2021 |
| Wibird Limited | Professional & scientific | 2014 |
| Wicem Ltd | Health & social care | 2020 |
| Wicken Toys Limited | Wholesale & retail | 2002 |
| Wicks Plant Ltd | Water & waste | 2025 |
| Wide Sky Investments Limited | Households | 2020 |
| Wifi Ltd | Information & communication | 2002 |
| Wifi Metropolis Limited | Administrative & support | 2016 |
| Wifi-Met UK Ltd | Administrative & support | 2018 |
| Wiginton Independent Genuine Iconic Spares Ltd | Wholesale & retail | 2026 |
| Wiki Holdings Limited | Financial services | 2026 |
| Wilcolaw Limited | Administrative & support | 2017 |
| Wild Benefits Ltd | Professional & scientific | 2025 |
| Wild Heather Food Company Limited | Hospitality | 2021 |
| Wild House Ltd | Hospitality | 2023 |
| Wild Technology Limited | Information & communication | 2009 |
| Wild-Side Brands Limited | Professional & scientific | 2012 |
| Wildberry Associates Limited | Wholesale & retail | 2019 |
| Wildercreative Limited | Manufacturing | 2007 |
| Wildfire Marketing Limited | Professional & scientific | 2016 |
| Wildfire Properties Ltd | Real estate | 2023 |
| Wildfire Property Holdings Ltd | Real estate | 2022 |
| Wildflower Construction Limited | Construction | 2024 |
| Wildflower Trading Ltd. | Administrative & support | 2016 |
| Wildlife and Birdcare Nature Recovery Project CIC | Health & social care | 2022 |
| Wilharo Limited | Information & communication | 2010 |
| Wilkins Consulting Ltd | Professional & scientific | 2013 |
| Will Family Care Limited | Health & social care | 2022 |
| Will Power Driving School Ltd | Education | 2024 |
| Will Trading Ltd | Transport & logistics | 2018 |
| Willen Coffee Ltd | Manufacturing | 2025 |
| Willen Electronics Limited | Professional & scientific | 2012 |
| Willen Hospice | Health & social care | 1975 |
| Willen Medical Services Limited | Real estate | 2004 |
| Willen Pavilion | Arts & recreation | 1991 |
| Willen Roofing and Cladding Limited | Construction | 2017 |
| Willen Spice Limited | Hospitality | 2024 |
| Willew Consulting Limited | Information & communication | 2015 |
| Willford Japanese Art Limited | Wholesale & retail | 2019 |
| William Clark (Holdings) Limited | Professional & scientific | 2016 |
| William Cojocaru Ltd | Wholesale & retail | 2022 |
| William Durden Construction Limited | Construction | 2026 |
| William Durden Developments Limited | Construction | 2026 |
| William Evans (Luton) Limited | Real estate | 1939 |
| William Herman Limited | Manufacturing | 2002 |
| William Meat Trader Ltd | Wholesale & retail | 2013 |
| William RAY Property Ltd | Construction | 2020 |
| William Sawbridge & Sons Ltd | Extraterritorial | 2016 |
| William Tennis Academy Ltd | Arts & recreation | 2018 |
| Williams and Henry Property Maintenance Ltd | Construction | 2015 |
| Williams and Henry Roofing Ltd | Construction | 2020 |
| Williams Building Services 1984 Limited | Construction | 2021 |
| Williams Express Limited | Water & waste | 2012 |
| Williams Family Properties Ltd | Real estate | 2025 |
| Williams Invest Limited | Professional & scientific | 2018 |
| Williams Leadership Development Ltd | Professional & scientific | 2012 |
| Williamson Cooling Limited | Construction | 2008 |
| Willie Jones Haulage Limited | Transport & logistics | 2007 |
| Willington Garden and Leisure Ltd | Wholesale & retail | 2018 |
| Willis & Tait Limited | Wholesale & retail | 2004 |
| Willoughby & Smets Accountants Limited | Real estate | 2018 |
| Willoughby Property Investments LLP | | 2026 |
| Willow Carpentry Limited | Manufacturing | 2025 |
| Willow Tree Holdings Ltd. | Financial services | 2015 |
| Willow Tree Housing Ltd | Real estate | 2023 |
| Willowberry Limited | Real estate | 2014 |
| Willowbridge Marina Limited | Manufacturing | 2008 |
| Willowbrite (Knowlhill) Limited | Real estate | 1999 |
| Willows Balloon Boutique Ltd | Arts & recreation | 2023 |
| Willsys Infosystems Limited | Information & communication | 2011 |
| Wilson Blue Property Management Ltd | Real estate | 2022 |
| Wilson Investments (2203) Ltd | Professional & scientific | 2022 |
| Wilson Price Machinery Group Ltd | Financial services | 2025 |
| Wilson's Deli & Coffee Ltd | Hospitality | 2021 |
| Wilstead Tandori Ltd | Hospitality | 2023 |
| Wiltons Benefits Ltd | Professional & scientific | 2023 |
| Wimborne Crescent Flats Management (NO 1) Limited | Households | 1994 |
| Wimborne Crescent Flats Management (NO 2) Limited | Households | 1995 |
| Wimpole 101 Limited | Transport & logistics | 2022 |
| WIN Wish Ltd | Information & communication | 2025 |
| Win-Mak Ltd | Health & social care | 2009 |
| Winbank Ltd | Wholesale & retail | 2006 |
| Wind Mobility Ltd | Administrative & support | 2020 |
| Windell Design Ltd | Construction | 2016 |
| Windmill Gardens Limited | Households | 1994 |
| Windmill Validation Services Limited | Professional & scientific | 2019 |
| Window Bits Limited | Wholesale & retail | 2024 |
| Windpulse Ltd | Other services | 2024 |