| Synergy Interim Management Limited | Professional & scientific | 2021 |
| T & E Wilson Property Limited | Construction | 2012 |
| T Connolly Plant and Agri Services Ltd | Manufacturing | 2025 |
| T Forsyth Building Services Ltd | Construction | 2012 |
| T Slinger Footwear Limited | Manufacturing | 2009 |
| T. & F.M. Grover Limited | Wholesale & retail | 1977 |
| T. K. Landscapes Limited | Administrative & support | 2002 |
| T.E.G. Yorkshire Ltd | Professional & scientific | 2014 |
| T.F Elleray Holdings Limited | Real estate | 2019 |
| TA Services (Yorkshire) Limited | Manufacturing | 2012 |
| Talbot Car Care Ltd | Administrative & support | 2007 |
| Tallboy Limited | Manufacturing | 2008 |
| Tamarisk Design Holdings Limited | Financial services | 2024 |
| Tanfield Engineering Services Limited | Professional & scientific | 2010 |
| Tannery Lane Autos Ltd | Wholesale & retail | 2021 |
| Tanzi Barbers Ltd | Other services | 2020 |
| Target Wellness & Integrated Safety Training Ltd | Education | 2025 |
| TASC2 Ltd | Health & social care | 2023 |
| Tate Property Group Ltd | Real estate | 2025 |
| Tate Wellness Coaching Ltd | Health & social care | 2025 |
| Taylor & Taylor Builders Ltd | Construction | 2026 |
| Taylors of Otley Limited | Wholesale & retail | 2013 |
| Taymech Limited | Administrative & support | 2016 |
| Tech Solutionz Ltd | Wholesale & retail | 2025 |
| Technical P Limited | Wholesale & retail | 2004 |
| Technowash Limited | Manufacturing | 2000 |
| Techwill Limited | Construction | 1992 |
| Teepee Investments Limited | Real estate | 2018 |
| Tees Online Doctor Ltd | Professional & scientific | 2026 |
| Tees Quality Consultants Limited | Professional & scientific | 2011 |
| Teesside Properties (North East) Limited | Real estate | 2015 |
| Teesside Steel Distribution Limited | Transport & logistics | 1996 |
| Temple FUN Limited | Arts & recreation | 2019 |
| Templepower Control Systems Limited | Professional & scientific | 2002 |
| Temporary Boiler Company Ltd | Construction | 2023 |
| Terrae Novo Limited | Water & waste | 2021 |
| Thai Massage & Nails House Ltd | Other services | 2025 |
| Thai Terminal Ltd | Hospitality | 2023 |
| THE Angel's Share Bakery Limited | Manufacturing | 2018 |
| THE Bedale Hunt | Arts & recreation | 2004 |
| THE Beeswing Inn (East Cowton) Limited | Hospitality | 2018 |
| THE Churchill Leadership Challenge | Other services | 2025 |
| THE Classic Touch Limited | Wholesale & retail | 2017 |
| THE Colour Haus Ltd | Other services | 2019 |
| THE Country Girls UK Limited | Arts & recreation | 2020 |
| THE Croft Property Co. Limited | Real estate | 2013 |
| THE Ethical Partnership Limited | Financial services | 2001 |
| THE Forum (Northallerton) Ltd | Arts & recreation | 2012 |
| THE Gilchrist Company (UK) Limited | Real estate | 2003 |
| THE Great North Art Show | Arts & recreation | 2009 |
| THE Green Apple Tree Ltd | Hospitality | 2017 |
| THE Health and Safety GUY Ltd | Professional & scientific | 2023 |
| THE Hill Cross Organisation Limited | Professional & scientific | 2012 |
| THE Joinery Co. (Northallerton) Limited | Manufacturing | 2024 |
| THE Jones Tool Company Limited | Other services | 1993 |
| THE Lean Consortium Limited | Professional & scientific | 2002 |
| THE Little Hippo Company Ltd | Manufacturing | 2019 |
| THE Motor House Arts CIC | Education | 2026 |
| THE Northallerton Hearing Practice Ltd | Wholesale & retail | 2025 |
| THE Oaks Farmers Limited | Agriculture & fishing | 2018 |
| THE Old R George Ltd | Hospitality | 2025 |
| THE Paper Boat Spirits Ltd | Professional & scientific | 2022 |
| THE Pendragon Community Trust | Health & social care | 2000 |
| THE Personal Potential Partnership Limited | Administrative & support | 2006 |
| THE Physio.Com Limited | Health & social care | 2005 |
| THE Real Hustler Limited | Wholesale & retail | 2018 |
| THE Stables (Northallerton) Management Company Limited | Real estate | 2007 |
| THE Thermal Snug Limited | Wholesale & retail | 2025 |
| THE Thoroughbred Agency Ltd | Real estate | 2003 |
| THE Vanity Rooms (Thirsk) Ltd | Other services | 2017 |
| THE Vanity Rooms Aesthetic Services Ltd | Health & social care | 2018 |
| THE Weavers Green Management Company Limited | Households | 2000 |
| THE Wedding Tribe Ltd | Other services | 2020 |
| THE Wheel Room Ltd | Extraterritorial | 2010 |
| THE Yorkshire NUT Company Limited | Manufacturing | 2020 |
| Theimageweb Limited | Information & communication | 2008 |
| Thesolescene Ltd | Wholesale & retail | 2020 |
| Theta Installations Limited | Construction | 2021 |
| Thimbleby Farms Limited | Agriculture & fishing | 1996 |
| Thimbleby Finance LLP | | 2010 |
| Think Beyond FM Limited | Professional & scientific | 2018 |
| Think Kitchen and Bathroom Limited | Wholesale & retail | 2002 |
| Thompson Butchers Limited | Hospitality | 2010 |
| Thornbrough Estate Limited | Real estate | 1985 |
| Thornton Bridge Farm Ltd | Agriculture & fishing | 2016 |
| Thoroughway Limited | Professional & scientific | 2021 |
| Thorpe Farm Rehabilitation and Fitness Ltd | Agriculture & fishing | 2021 |
| Tillasu Estates Limited | Real estate | 1946 |
| Timberwolf Homes Ltd | Construction | 2025 |
| Times 2 Studios Ltd | Professional & scientific | 2013 |
| Timmons Electrical Ltd | Professional & scientific | 2024 |
| TJP Consultants Ltd | Professional & scientific | 2015 |
| Tmbpj Limited | Construction | 2026 |
| Toats Granola Ltd | Manufacturing | 2025 |
| Tonnerre Consulting Limited | Professional & scientific | 2016 |
| Tony Walker Construction Limited | Professional & scientific | 2020 |
| Tool Safe Solutions Limited | Wholesale & retail | 2025 |
| Toothfairy Inc Ltd | Other services | 2019 |
| Tornum Limited | Manufacturing | 1999 |
| Total Gutter Maintenance Limited | Administrative & support | 1997 |