| Tina Prop Limited | Real estate | 2025 |
| Tipichic Limited | Hospitality | 2015 |
| Titan Trustees Limited | Extraterritorial | 2011 |
| TKD Consultancy Ltd | Professional & scientific | 2017 |
| TLG Properties and Investments Ltd | Real estate | 2021 |
| TLM Roofing Ltd | Construction | 2024 |
| TM Accountancy and Finance Ltd | Professional & scientific | 2020 |
| TM Welch Properties Ltd | Real estate | 2018 |
| Tmmo Transport Ltd | Transport & logistics | 2017 |
| TMW Projects Limited | Administrative & support | 2023 |
| Tnkp Limited | Hospitality | 2025 |
| TNM Properties NE Ltd | Real estate | 2024 |
| TNT Housing Ltd | Extraterritorial | 2024 |
| Todd Fall Leisure Ltd | Hospitality | 2021 |
| Todd Solutions Ltd | Professional & scientific | 2021 |
| Tofta Properties Ltd | Real estate | 2019 |
| Tohyg Yiore Ltd | Wholesale & retail | 2026 |
| Tollins Holdings Ltd | Real estate | 2023 |
| TOM Cook Carpets Limited | Wholesale & retail | 2009 |
| TOM Craddock Football Academy Limited | Education | 2021 |
| TOM Hunter Coaching Ltd | Health & social care | 2025 |
| TOM Stammer Solutions Ltd | Professional & scientific | 2013 |
| Tompkins Investments Limited | Professional & scientific | 2010 |
| Tony Nguyen Nails Ltd | Other services | 2024 |
| Tonys High Grange Limited | Hospitality | 2026 |
| Toothwise Clinic Limited | Health & social care | 2018 |
| Toothwise Limited | Health & social care | 2006 |
| Top Spec Window Cleaning Ltd | Administrative & support | 2025 |
| TOP4TIERS Limited | Arts & recreation | 2022 |
| Topaz Luxe Ltd | Wholesale & retail | 2018 |
| Tornado Merchandising Limited | Wholesale & retail | 2010 |
| Tornado Steam Traction Limited | Transport & logistics | 2001 |
| Toross Pizzaria Ltd | Hospitality | 2024 |
| Torque Calibration Ltd | Manufacturing | 2012 |
| Total Accident Management Limited | Transport & logistics | 1996 |
| Total Building Supplies NE Ltd | Wholesale & retail | 2026 |
| Total Cleaning Services Group Ltd | Administrative & support | 2017 |
| Total Health 360 Limited | Health & social care | 2026 |
| Total Plastics Limited | Construction | 2019 |
| Total Rental Solutions Ltd | Administrative & support | 2016 |
| Total Solution & Service Limited | Construction | 2010 |
| Total Tax & Accountancy Solutions Ltd | Professional & scientific | 2018 |
| Total Tax Solutions (Group) Limited | Professional & scientific | 2021 |
| Total Tax Solutions (Teesside) Limited | Professional & scientific | 2013 |
| Total Tax Solutons(Property) Limited | Professional & scientific | 2014 |
| Toucan Technology Ltd | Professional & scientific | 2019 |
| Tour Pro Golf Group Ltd | Wholesale & retail | 2021 |
| Towed by Lewis Ltd | Administrative & support | 2026 |
| Towers Roofing and Cladding TRC Limited | Construction | 2025 |
| Town & City Directors Ltd | Households | 2007 |
| Town & City Management Limited | Households | 2009 |
| Town & City Secretaries Ltd | Households | 2007 |
| Townhead Chippy Limited | Hospitality | 2014 |
| Toyah Limited | Wholesale & retail | 2026 |
| TQ Clover Limited | Wholesale & retail | 2023 |
| Tracks Darlington Community Interest Company | Arts & recreation | 2019 |
| Trade Cars NE Ltd | Wholesale & retail | 2024 |
| Trade Counter Flooring Ltd | Administrative & support | 2017 |
| Trade Hair Supplies Limited | Wholesale & retail | 2004 |
| Trade Valley VAE Ltd | Construction | 2022 |
| Tradefair Properties Ltd | Real estate | 2005 |
| Traderiser Limited | Information & communication | 2014 |
| Traditional Hospitality Community Development Community Interest Company | Hospitality | 2021 |
| Trafalgar Productions Limited | Information & communication | 2009 |
| Trajectory Cloud Ltd | Information & communication | 2026 |
| Transaction Automation Trading Ltd | Wholesale & retail | 2025 |
| Transchris Ltd | Transport & logistics | 2015 |
| Transelectric Ltd | Construction | 2023 |
| Transform Psychology Ltd | Education | 2022 |
| Transport Recruitment & Co Ltd | Administrative & support | 2025 |
| Transport Solutions NE Limited | Transport & logistics | 2022 |
| Trash Productions Ltd | Information & communication | 2017 |
| Travellers Rest (Evenwood) Limited | Hospitality | 2020 |
| Trebe Ltd. | Information & communication | 2014 |
| Tree BOY Ltd | Arts & recreation | 2023 |
| Trendsetters Display Graphics Limited | Manufacturing | 2013 |
| Trevelyan Assets & Holdings Limited | Financial services | 2023 |
| TRH Love Ltd | Real estate | 2023 |
| Triart Limited | Wholesale & retail | 2003 |
| Tribe 365 Ltd | Information & communication | 2019 |
| Tribe Executive Search Limited | Administrative & support | 2009 |
| Tribe Recruitment Limited | Administrative & support | 2009 |
| Tribeca 1 Limited | Construction | 1989 |
| Trident Manor Limited | Professional & scientific | 2013 |
| Trident Manor Protective Services Limited | Administrative & support | 2020 |
| Trip Merc Ltd | Administrative & support | 2019 |
| Triplegate Properties Limited | Real estate | 2012 |
| Triplegate Property Developments Limited | Real estate | 2000 |
| Trish Medrano Haste Ltd | Professional & scientific | 2022 |
| Trish Summers & Co Limited | Professional & scientific | 2014 |
| Trivelli Developments Ltd | Extraterritorial | 2024 |
| TRN Group Limited | Health & social care | 2022 |
| Trophycentre (UK) Limited | Wholesale & retail | 2003 |
| TRS Humberside Ltd | Administrative & support | 2026 |
| TRS Rental Group Ltd | Financial services | 2026 |
| TRS Support Services Ltd | Administrative & support | 2026 |
| TRS Test & CAL Ltd | Administrative & support | 2026 |
| TRU Beauty Darlington Ltd | Other services | 2024 |
| Tru-Blu Financial Limited | Financial services | 2019 |
| Truck Clean Ltd | Administrative & support | 2020 |