| W. Smith (Durham) Limited | Wholesale & retail | 1974 |
| WAC Holdings NE Ltd | Financial services | 2025 |
| Waffley Good Company Ltd | Hospitality | 2026 |
| Waggott Bros Limited | Wholesale & retail | 2018 |
| Wakari Limited | Information & communication | 2023 |
| Waletta Global Ltd | Wholesale & retail | 2024 |
| Walkabout Durham- City Walking Tours Ltd | Administrative & support | 2026 |
| Walker Tyres Limited | Wholesale & retail | 2003 |
| Walkers Butchers & Bakers Ltd | Wholesale & retail | 2003 |
| Walkers Furniture Stores Limited | Wholesale & retail | 2019 |
| Wall AID Services Limited | Construction | 2024 |
| Wallace Aviation Limited | Manufacturing | 2014 |
| Wallondes Ltd | Wholesale & retail | 2025 |
| WAM Tech Ltd | Information & communication | 2025 |
| Warcup Properties Ltd | Construction | 2022 |
| Ward Group Investments Ltd | Households | 2021 |
| Ward Group Management Limited | Construction | 2017 |
| Ward Group North Road Ltd | Real estate | 2022 |
| Warm Sanctuary Limited | Wholesale & retail | 2009 |
| Water and Environmental Resources Management Limited | Professional & scientific | 2022 |
| Water Efficiency Services Limited | Extraterritorial | 2025 |
| Waterco SIX Limited | Professional & scientific | 1990 |
| Waterstons Limited | Information & communication | 1999 |
| Watson & Co. Photography Ltd | Professional & scientific | 2025 |
| Watson & SON Construction Ltd | Construction | 2019 |
| Watson & SON Plant Hire Ltd | Administrative & support | 2015 |
| Watson Build & Green Energy Limited | Construction | 2025 |
| Watt Site Services Limited | Professional & scientific | 2022 |
| Watts UP Consulting Ltd | Energy | 2024 |
| Wave Ltd | Professional & scientific | 2008 |
| Wave Utilities Limited | Extraterritorial | 2000 |
| Waxology Ltd | Other services | 2018 |
| Waythrough | Health & social care | 1984 |
| Waytowealth Ltd | Wholesale & retail | 2025 |
| Wbco Clinic Limited | Other services | 2021 |
| WBL Groundworks Ltd | Construction | 2020 |
| WD Event Medics Ltd | Health & social care | 2025 |
| WD Security Group North East Ltd | Public administration | 2025 |
| WE ARE Feast Ltd | Wholesale & retail | 2025 |
| Wealth of Advice Limited | Financial services | 2011 |
| Wear Rivers Trust | Other services | 2001 |
| Weardale Lithium Limited | Mining & quarrying | 2018 |
| Wearecura Ltd | Information & communication | 2026 |
| Wearside Bathrooms Ltd | Construction | 2025 |
| Wearside Care Ltd | Health & social care | 2017 |
| Wearside Coins Ltd | Wholesale & retail | 2024 |
| Wearside Investments Limited | Real estate | 2010 |
| Wearview Holdings Ltd | Real estate | 2020 |
| Weatherston & Sons Ltd | Construction | 2022 |
| Webb DEV Ltd | Information & communication | 2025 |
| Wellbeing Lead Academy Ltd | Education | 2024 |
| Wellbridge Consultancy Limited | Professional & scientific | 2023 |
| Wellbridge Limited | Real estate | 2022 |
| Wellsprings Meadowfield Limited | Real estate | 2009 |
| West Durham BNG Limited | Agriculture & fishing | 2024 |
| West Hall Cottage Limited | Hospitality | 2020 |
| West London Immigration Services Limited | Professional & scientific | 2013 |
| West Park Financial Planning Ltd | Professional & scientific | 2017 |
| West Park JV Limited | Real estate | 2017 |
| West Road Garage Limited | Wholesale & retail | 2019 |
| Westfield EFW SPV Limited | Real estate | 2023 |
| Westfield Solar SPV Limited | Real estate | 2023 |
| Westfield Windfarm SPV Limited | Real estate | 2023 |
| Westfirst Limited | Real estate | 1994 |
| Westholme House Ltd | Real estate | 2023 |
| WF6 Investments Limited | Real estate | 2025 |
| Whartons Properties Ltd | Real estate | 2021 |
| Whatworked Education Ltd | Education | 2020 |
| Wheatley Hearing Solutions Ltd | Health & social care | 2024 |
| Wheatley Hill Limited | Construction | 2016 |
| Whistling Mule Productions Limited | Other services | 1996 |
| White and Soul Ltd | Real estate | 2023 |
| White Lyon Films Ltd | Administrative & support | 2008 |
| White Rose Housing Ltd | Real estate | 2023 |
| White Rose Teaching Ltd | Administrative & support | 2024 |
| Whitechurch Durham Limited | Hospitality | 2017 |
| Whitechurch Upnorth Limited | Hospitality | 2018 |
| Whitfield Court Development Management Company Limited | Real estate | 2011 |
| Whitfield Financial Consulting Limited | Professional & scientific | 2016 |
| Whitfield Flooring Dunfermline Limited | Wholesale & retail | 2025 |
| Whitfield Flooring Kirkcaldy Limited | Wholesale & retail | 2025 |
| Whitingandsons Ltd | Real estate | 2019 |
| Whitwell Media Limited | Information & communication | 2019 |
| WHW Print Limited | Manufacturing | 2011 |
| WHY Hyde Limited | Wholesale & retail | 2017 |
| Wigwam Property Group Limited | Real estate | 2021 |
| Wiiz Properties Limited | Real estate | 2021 |
| Wild & Dandy Events Limited | Wholesale & retail | 2025 |
| Wild and Dandy Limited | Wholesale & retail | 2017 |
| Wild at Heart Florists Ltd. | Wholesale & retail | 2018 |
| Wild Bloom C.I.C. | Arts & recreation | 2025 |
| Wildspacegroup Ltd | Public administration | 2025 |
| Wilkinson Autos Limited | Professional & scientific | 2022 |
| Willchris Limited | Real estate | 2024 |
| Willis Addison Ltd | Real estate | 2020 |
| Willmore Mortgage Solutions Limited | Financial services | 2025 |
| Willow Bloom Group Limited | Health & social care | 2023 |
| Willow Manor Limited | Wholesale & retail | 2021 |
| Willow Park Investments 2 Limited | Financial services | 2025 |
| Willow's Flowers Ltd | Wholesale & retail | 2025 |