| THE Teak Furniture Company Limited | Wholesale & retail | 2023 |
| THE Urban Deli Darlington Limited | Hospitality | 2023 |
| THE White Rose School of Beauty and Complementary Therapies Limited | Education | 1996 |
| THE Young Group Limited | Construction | 2021 |
| Thebreadtrade Ltd | Wholesale & retail | 2024 |
| Thomas Aldus Property Ltd | Real estate | 2023 |
| Thompson Rope Access Ltd | Professional & scientific | 2014 |
| Thoroughgood Advantage Ltd | Real estate | 2025 |
| TIN Arts Limited | Arts & recreation | 2005 |
| Tingle Leisure Limited | Arts & recreation | 2025 |
| Tinkle Guard Ltd | Health & social care | 2011 |
| Tiny Teas Trust Ltd | Wholesale & retail | 2024 |
| TKM Global Ltd | Wholesale & retail | 2025 |
| TKM Leisure Ltd | Hospitality | 2021 |
| TLB Accountancy Ltd | Professional & scientific | 2010 |
| Tlqmark Ltd | Wholesale & retail | 2024 |
| Together - Zackary and Karlene C.I.C. | Health & social care | 2024 |
| Tonicwave Ltd | Wholesale & retail | 2025 |
| Torben Consulting Ltd | Professional & scientific | 2023 |
| Tosola Chemicals and Pharmaceutical Services Limited | Health & social care | 2011 |
| Total Bathrooms Limited | Construction | 2006 |
| Treadmark Tyres and Autocentre Limited | Wholesale & retail | 2012 |
| Treadmark Tyres North East Limited | Wholesale & retail | 2023 |
| Treetop Joinery North East Limited | Manufacturing | 2016 |
| Trendora Trade Ltd | Wholesale & retail | 2026 |
| Trevalis Ltd | Wholesale & retail | 2026 |
| Triplax Measurement Services Ltd | Professional & scientific | 2022 |
| Tropicana Tanning & Beauty Limited | Other services | 2015 |
| Tudhoe Hall Residents Company Limited | Administrative & support | 1997 |
| Tudhoe Learning Trust | Education | 2012 |
| Turgan & Co Ltd | Wholesale & retail | 2025 |
| Tyre Recovery Limited | Wholesale & retail | 2002 |
| U-Pm.Com Limited | Information & communication | 2007 |
| Ultratan Sunbed Hire North East Ltd | Other services | 2020 |
| Urban Serenity Limited | Education | 2015 |
| Vallum Industries Limited | Professional & scientific | 2020 |
| Vanira Ltd | Wholesale & retail | 2025 |
| Vellora Trade Ltd | Wholesale & retail | 2026 |
| Velora Store Ltd | Wholesale & retail | 2026 |
| Velore Trade Ltd | Wholesale & retail | 2026 |
| Ventrox Global Ltd | Wholesale & retail | 2025 |
| Verde Commerce Ltd | Wholesale & retail | 2025 |
| Viridis Alliance Ltd | Administrative & support | 2023 |
| Virtually Limitless Limited | Administrative & support | 2019 |
| Visual Signs Limited | Other services | 2009 |
| Voltrix Trade Ltd | Wholesale & retail | 2026 |
| Vorvans Ltd | Wholesale & retail | 2026 |
| VP F&M Ltd. | Professional & scientific | 2018 |
| Wear Valley Foods (Co Durham) Ltd | Hospitality | 2024 |
| Westbridge Retail Ltd | Wholesale & retail | 2026 |
| Wexford Market Ltd | Wholesale & retail | 2025 |
| WF1 Property Management Ltd | Real estate | 2023 |
| Wheat Grains Global Ltd | Wholesale & retail | 2025 |
| White Wolf Trade Ltd | Wholesale & retail | 2026 |
| WILL2SUCCEED Consultancy Services Limited | Administrative & support | 2015 |
| Wilson Industrial NE Ltd | Professional & scientific | 2025 |
| Wise Imports Limited | Wholesale & retail | 2017 |
| Womma Ltd | Wholesale & retail | 2025 |
| Workwise Personnel Limited | Administrative & support | 2002 |
| Worlds Awakened Ltd | Administrative & support | 2026 |
| Xart Global Ltd | Wholesale & retail | 2026 |
| Xtend Aesthetics Limited | Other services | 2024 |
| Yahpharm Ltd | Health & social care | 2021 |
| Yamev Brands Ltd | Wholesale & retail | 2026 |
| Yarenshop Ltd | Wholesale & retail | 2025 |
| Yeliz Kirac Ltd | Wholesale & retail | 2026 |
| YLM Trade Ltd | Wholesale & retail | 2025 |
| Your Oasys Lounge Community Interest Company | Other services | 2014 |
| Your Property Stop Limited | Real estate | 2017 |
| YT Trade Ltd | Wholesale & retail | 2025 |
| Yummy Valley Limited | Hospitality | 2024 |
| Yunico Inc Ltd | Wholesale & retail | 2025 |
| Zedsla UK Limited | Real estate | 2024 |
| Zedsor Limited | Wholesale & retail | 2021 |
| Zeftan Ltd | Other services | 2014 |
| Zenith Key Ltd | Wholesale & retail | 2025 |
| Zentix Ltd | Information & communication | 2025 |
| Zerust (UK) Limited | Manufacturing | 1996 |
| Zeyap Global Ltd | Wholesale & retail | 2025 |
| Zeyra Trade Ltd | Wholesale & retail | 2026 |
| Zonz Ltd | Transport & logistics | 2023 |
| Zuhatori Ltd | Transport & logistics | 2026 |
| Zyrova Ltd | Wholesale & retail | 2025 |