| Teesside Tanning and Aesthetics Ltd | Other services | 2018 |
| Teesside Transport Limited | Transport & logistics | 2025 |
| Teesside Transport Training Limited | Education | 2003 |
| Teesside Travel Ltd | Transport & logistics | 2025 |
| Teesside Virtual Property Consultants Ltd | Information & communication | 2019 |
| Teesside Window Cleaning Ltd | Administrative & support | 2019 |
| Teesside Windows Limited | Construction | 1995 |
| Teesvalley Womens Centre Ltd | Education | 2004 |
| Teeswick General Ltd | Wholesale & retail | 2026 |
| TEF Engineering Services Ltd | Other services | 2017 |
| TEG Safety Ltd | Professional & scientific | 2025 |
| Tejas Solutions Limited | Professional & scientific | 2017 |
| Tekbuild Ltd | Construction | 2017 |
| Tekconstruct Ltd | Construction | 2020 |
| Tekcontracting Ltd | Construction | 2021 |
| Tekframe Ltd | Construction | 2020 |
| Tekmerchant Ltd | Wholesale & retail | 2023 |
| TEL Communications Limited | Information & communication | 2018 |
| Telcoss Engineering Limited | Professional & scientific | 2025 |
| Telectronics Limited | Professional & scientific | 2013 |
| Telefy Limited | Information & communication | 2025 |
| Teletom Ltd | Construction | 2025 |
| Telford Furniture Ltd | Wholesale & retail | 2025 |
| Temolar Limited | Professional & scientific | 2023 |
| Temple Safety Group Ltd | Professional & scientific | 2025 |
| Tensixtwo Communications Limited | Administrative & support | 2013 |
| Tenzing Experience Limited | Professional & scientific | 2015 |
| Terri by Singleton Ltd | Wholesale & retail | 2025 |
| Terry Cody Engineering Limited | Administrative & support | 2013 |
| Tester's Electrical Solutions Ltd | Construction | 2018 |
| TF Construction Group Ltd | Construction | 2024 |
| TFL Styles Ltd | Manufacturing | 2025 |
| TG Sparkle Solutions Limited | Wholesale & retail | 2025 |
| TGA Projects Limited | Professional & scientific | 2025 |
| Tgaffneltd Ltd | Manufacturing | 2025 |
| Tghjp Limited | Hospitality | 2024 |
| Tgm-Energy Ltd | Professional & scientific | 2025 |
| Tgtw Downes Holdings Ltd | Real estate | 2025 |
| TH Mechanical Engineering (NE) Limited Limited | Professional & scientific | 2016 |
| TH Services (NE) Limited | Professional & scientific | 2013 |
| Thai Fridays Ltd | Hospitality | 2026 |
| Thdcateringboro Limited | Hospitality | 2022 |
| THE Academy Teesside Ltd | Education | 2025 |
| THE Access Language Agency Limited | Professional & scientific | 2022 |
| THE Achieve Group International (Holdings) Limited | Professional & scientific | 2023 |
| THE Angle Sports & Entertainment Ltd | Arts & recreation | 2024 |
| THE Annex Airgun Range Teeside Ltd | Arts & recreation | 2024 |
| THE Aquatic Store Limited | Wholesale & retail | 2025 |
| THE Associates Psychological Services Limited | Health & social care | 2013 |
| THE Auxiliary Project Space CIC | Arts & recreation | 2017 |
| THE Avenue Day Nursery Ltd | Education | 2011 |
| THE Aylo Edit Limited | Wholesale & retail | 2025 |
| THE Ayton Water Company Limited | Water & waste | 1987 |
| THE Bakers Cabin Limited | Hospitality | 2010 |
| THE Bean Espresso Ltd | Hospitality | 2010 |
| THE Beautiful Blind Co. Limited | Wholesale & retail | 2013 |
| THE Beautiful Flooring Company (NE) Ltd | Wholesale & retail | 2018 |
| THE Beautiful Shutter Company Ltd | Wholesale & retail | 2015 |
| THE Believe Boutique Limited | Hospitality | 2023 |
| THE Benison Christopher Company Ltd | Information & communication | 2023 |
| THE Better YOU Academy Limited | Education | 2022 |
| THE Big Tute Ltd | Hospitality | 2020 |
| THE Bointon Group Limited | Real estate | 2025 |
| THE Bothy Ltd | Hospitality | 2022 |
| THE Bottled Note Ltd | Hospitality | 2017 |
| THE BRA Clinic Ltd | Wholesale & retail | 2005 |
| THE Burlam Bear Ltd Ltd | Hospitality | 2024 |
| THE Buzzing Bean Café Ltd | Hospitality | 2024 |
| THE C-Store Collective Ltd | Professional & scientific | 2019 |
| THE C-Store Group Ltd | Professional & scientific | 2019 |
| THE Carpet Warehouse NE Ltd | Wholesale & retail | 2025 |
| THE Chairman at Bedford Street Ltd | Hospitality | 2022 |
| THE Change Tribe Consultancy Limited | Professional & scientific | 2009 |
| THE Chief Music Ltd | Information & communication | 2022 |
| THE Children’S Eczema Clinic Ltd | Health & social care | 2024 |
| THE Clinkard Group Limited | Wholesale & retail | 1992 |
| THE Clover Foundation C.I.C. | Health & social care | 2018 |
| THE Cobblers and Cleveland Inn Ltd | Hospitality | 2023 |
| THE Competition MAN Ltd | Wholesale & retail | 2025 |
| THE Connection Collective Ltd | Health & social care | 2020 |
| THE Cosy Plate Cafe Limited | Hospitality | 2026 |
| THE Craft Movement Limited | Hospitality | 2020 |
| THE Crescent Lodge Limited | Real estate | 1960 |
| THE Cullinan Saas Smith Limited | Information & communication | 2025 |
| THE Culture Element Ltd | Administrative & support | 2025 |
| THE DEN Boro Ltd | Hospitality | 2026 |
| THE Devils PUB Ltd | Hospitality | 2024 |
| THE Digital North Sea Limited | Other services | 2018 |
| THE Divine Greek (NE) Ltd | Hospitality | 2024 |
| THE Dream Reno Limited | Construction | 2025 |
| THE Eco Threads Project CIC | Education | 2025 |
| THE Emots Ltd | Information & communication | 2024 |
| THE Empire Grand Hotel Co. Ltd | Hospitality | 2025 |
| THE Empire Grand Hotel Middlesbrough Limited | Hospitality | 2026 |
| THE Emporium Trading Ltd | Wholesale & retail | 2008 |
| THE Endeavour Foundation | Other services | 2024 |
| THE ESG Energy Company Ltd | Other services | 2021 |
| THE Facilitation Partnership Ltd | Other services | 2013 |
| THE Farmhouse Kitchen (M'Bro) Ltd | Hospitality | 2025 |
| THE Fite Brand Ltd | Wholesale & retail | 2025 |