| Teece Media Limited | Information & communication | 2012 |
| Tees Advisory Services Ltd | Professional & scientific | 2026 |
| Tees Global Ltd | Information & communication | 2020 |
| Tees Mech Ltd | Extraterritorial | 2020 |
| Tees Neuro Physiotherapy Limited | Health & social care | 2018 |
| Tees Valley Apprenticeships Ltd | Administrative & support | 2019 |
| Tees Valley Fencing and Gates Limited | Manufacturing | 2022 |
| Tees-Side Welding Equipment Company Limited | Wholesale & retail | 1965 |
| Teeside Door Services Ltd | Manufacturing | 2026 |
| Teesside Box CUP Limited | Arts & recreation | 2026 |
| Teesside Centre of Health and Performance Limited | Arts & recreation | 2023 |
| Teesside Elevators and Fabrications Limited | Manufacturing | 2013 |
| Teesside Industrial Services Holdings Limited | Financial services | 2025 |
| Teesside Lions Ltd | Arts & recreation | 2018 |
| Teesside LLP | | 2015 |
| Teesside Media Limited | Professional & scientific | 2019 |
| Teesside Medical Services Ltd | Health & social care | 2023 |
| Teesside Property Management Ltd | Real estate | 2021 |
| Teesside Security Services Limited | Administrative & support | 2008 |
| Teesside Site Services Limited | Administrative & support | 2007 |
| Teesside Sports Outreach CIC | Education | 2026 |
| Teesside Trade Cars Ltd | Wholesale & retail | 2010 |
| Teesside Van's Ltd | Manufacturing | 2022 |
| Teessideepc Ltd | Professional & scientific | 2025 |
| Teestec Limited | Information & communication | 2025 |
| Teestech Joinery Ltd | Manufacturing | 2014 |
| Teesworks Benevolent Foundation | Professional & scientific | 2023 |
| Temp Tester - Tech Limited | Wholesale & retail | 2023 |
| Tempest Estates Limited | Agriculture & fishing | 2004 |
| Tempest Health Ltd | Health & social care | 2025 |
| Tenet Partnership LLP | | 2018 |
| Tern Integrity Ltd | Professional & scientific | 2026 |
| Terry Eaton Building Services Limited | Construction | 2010 |
| TFS Holdings Limited | Real estate | 2025 |
| Thavam Express Ltd | Wholesale & retail | 2018 |
| Thayar Projects Ltd | Health & social care | 2024 |
| THE Allen's Family Holdings Ltd | Real estate | 2020 |
| THE Allen's Family Partnership LLP | | 2020 |
| THE Ashes MGM Co Ltd | Other services | 2024 |
| THE Ashforth Consultancy Limited | Professional & scientific | 2018 |
| THE Brewer & Firkin (Hartlepool) Company Limited | Real estate | 1993 |
| THE Castle Group (NW) Limited | Real estate | 2021 |
| THE Casual Comp Ltd | Wholesale & retail | 2025 |
| THE Coffee POT Billingham Limited | Hospitality | 2022 |
| THE Cozy Cafe Billingham Limited | Hospitality | 2026 |
| THE Desserts Corner Limited | Hospitality | 2024 |
| THE Eyley Group Ltd | Professional & scientific | 2022 |
| THE Facilitator Consulting Ltd | Professional & scientific | 2024 |
| THE Funding Forum Limited | Administrative & support | 2012 |
| THE Furry Dogmother Ltd | Other services | 2020 |
| THE Garden Bar and Lounge Ltd | Hospitality | 2018 |
| THE Girls House Limited | Other services | 2023 |
| THE Global Routes Corporation Ltd | Arts & recreation | 1987 |
| THE Green Hops Bar Ltd | Hospitality | 2017 |
| THE Hoppings Limited | Other services | 2013 |
| THE House That JIM Built Ltd | Real estate | 2019 |
| THE Innocent Family LLP | | 2017 |
| THE Innovation Boutique Limited | Arts & recreation | 2011 |
| THE Insight to Impact Collective Ltd | Professional & scientific | 2026 |
| THE Ivory Castle Limited | Health & social care | 2025 |
| THE Joan and Jude Way Play Cafe Ltd | Hospitality | 2025 |
| THE Knowledge Vault Limited | Information & communication | 2025 |
| THE Lunt Group Ltd | Financial services | 2025 |
| THE Malick Family Holdings Ltd | Real estate | 2018 |
| THE Malick Family Partnership LLP | | 2018 |
| THE Mnfi Limited Partnership | | 2007 |
| THE Pagan Group Ltd | Professional & scientific | 2022 |
| THE Peaceful Baby Company Limited | Education | 2015 |
| THE Pest Technician Limited | Agriculture & fishing | 2017 |
| THE Physio Department Ltd | Health & social care | 2009 |
| THE Play PAD Limited | Health & social care | 2025 |
| THE Porky Pint PUB Company Limited | Hospitality | 2023 |
| THE Property Buying Team Ltd | Real estate | 2020 |
| THE Property Team Ltd | Construction | 2012 |
| THE Rekalibrator C.I.C. | Education | 2022 |
| THE Reupholstery Centre Ltd | Wholesale & retail | 2014 |
| THE Roath Real Estate Limited | Real estate | 2018 |
| THE Rsln Business Ltd | Real estate | 2025 |
| THE Smiths 2025 Ltd | Hospitality | 2025 |
| THE Social Method Ltd | Professional & scientific | 2025 |
| THE Source Force Ltd | Information & communication | 2025 |
| THE Sporting Club Limited | Construction | 1996 |
| THE Striking Apparel and Equipment Company Ltd | Manufacturing | 2026 |
| THE Suntrap Bar Ltd | Hospitality | 2024 |
| THE Swainston Group Limited | Extraterritorial | 2024 |
| THE Tees Media CIC | Manufacturing | 2021 |
| THE Training Team (Tyas) Limited | Administrative & support | 2012 |
| THE Trigger Business Ltd | Real estate | 2008 |
| THE Vape Shack Billingham Ltd | Wholesale & retail | 2026 |
| THE Village Football Company Ltd | Arts & recreation | 2023 |
| THE Ward Family Holdings Ltd | Real estate | 2019 |
| THE Ward Family Partnership LLP | | 2019 |
| THE Watt Group (North East) Demolition Limited | Construction | 2019 |
| THE Whitehouse Partnership LLP | | 2021 |
| THE Wynyard Candle Company Limited | Wholesale & retail | 2024 |
| THE Wynyard Hotel Limited | Hospitality | 2004 |
| Thephysiotherapydoc Ltd | Other services | 2021 |
| Therese Street LLP | | 2023 |
| Think Innovative Ltd | Professional & scientific | 2009 |
| Think Mediation Ltd | Other services | 2020 |