| THE Stepz Group Ltd | Health & social care | 2021 |
| THE Studio North East Ltd | Professional & scientific | 2021 |
| THE Tanning Company Ltd | Other services | 2024 |
| THE Taste of Shinwari Ltd | Hospitality | 2021 |
| THE Teesside Charity | Professional & scientific | 2010 |
| THE Therapy Centre @ Marton Ltd | Health & social care | 2018 |
| THE TIC Academy Limited | Education | 2023 |
| THE Tomcan Group Limited | Other services | 2022 |
| THE Traditional Romanian Restaurant Ltd | Hospitality | 2023 |
| THE Travelling Artisan Ltd | Manufacturing | 2017 |
| THE Trove Events Ltd | Other services | 2020 |
| THE Truffled HOG Group Limited | Professional & scientific | 2025 |
| THE Truffled HOG Limited | Wholesale & retail | 2020 |
| THE Truffled HOG Stokesley Ltd | Hospitality | 2025 |
| THE Twisted LIP Ltd | Hospitality | 2014 |
| THE Ubuntu Training Company Limited | Education | 2012 |
| THE Unicorn Pool Ltd | Arts & recreation | 2023 |
| THE Unit Functional Gym Limited | Arts & recreation | 2017 |
| THE Vape Shack NE Limited | Wholesale & retail | 2024 |
| THE Very Enterprising Community Interest Company | Education | 2011 |
| THE VET Collective Ltd | Professional & scientific | 2024 |
| THE Warm Welcome Cafe Ltd | Hospitality | 2025 |
| THE Watch Crowd Ltd | Wholesale & retail | 2021 |
| THE Western Club Limited | Hospitality | 2026 |
| THE Wild Haven Project CIC | Education | 2025 |
| THE ZED Shop Ltd | Wholesale & retail | 2025 |
| THE ZOO Middlesbrough CIC | Wholesale & retail | 2025 |
| Thecurryspot Limited | Hospitality | 2025 |
| Theivam Property Investment Ltd | Real estate | 2025 |
| Theloftguys Ltd | Construction | 2026 |
| Thenaughtyhabit Limited | Hospitality | 2025 |
| Theperfumez Limited | Wholesale & retail | 2026 |
| Thepropertysmith Ltd | Real estate | 2023 |
| Thermal Engineering Solutions Ltd | Manufacturing | 2024 |
| Thermedge Limited | Construction | 2023 |
| Thermoflex Ltd | Construction | 2025 |
| Therobinman Ltd | Arts & recreation | 2011 |
| Theshedcafe Limited | Hospitality | 2026 |
| Thfo Ltd | Wholesale & retail | 2026 |
| Thibex Auto Limited | Manufacturing | 2025 |
| Think Developments (UK) Ltd | Professional & scientific | 2014 |
| Thinking Advisory Limited | Professional & scientific | 2026 |
| Third Nature Ltd | Professional & scientific | 2025 |
| Thirlwells Estate Agents Limited | Real estate | 2019 |
| Thirlwells TS1 Limited | Real estate | 2019 |
| Thirsk Management Consultants Ltd | Administrative & support | 2023 |
| Thirteen Commercial Services Limited | Professional & scientific | 2002 |
| Thirteen Homes Limited | Construction | 1997 |
| Thirteen Property Development Limited | Construction | 2005 |
| Thirteen Social Enterprises Limited | Real estate | 2010 |
| Thirteen Supply Co (NE) Limited | Professional & scientific | 2021 |
| Thirty Two Original Ltd | Health & social care | 2017 |
| Thistle Rail Limited | Construction | 2012 |
| THM Investments Limited | Financial services | 2025 |
| Thomasmarkltd Ltd | Professional & scientific | 2025 |
| Thompsons Hardware Ltd | Wholesale & retail | 2009 |
| Thornlea (Darlington) Management Company Limited | Households | 1996 |
| Thornton Drainage Services Limited | Water & waste | 2018 |
| Thornton Wain Developments Ltd | Real estate | 2022 |
| Thorpland Developments Ltd | Construction | 2020 |
| Three Keys Renovations Ltd | Real estate | 2025 |
| Three Legged Music Limited | Information & communication | 2021 |
| Three Peaks Technical Consulting Ltd | Professional & scientific | 2018 |
| Three Trees Venture Limited | Wholesale & retail | 2021 |
| Thriftvoyage Ltd | Wholesale & retail | 2023 |
| Thrive North East CIC | Information & communication | 2026 |
| Thrybergh Motor Services Limited | Wholesale & retail | 2018 |
| Thunder Essentials Company Limited | Wholesale & retail | 2020 |
| TIA Hama Valeting Ltd | Administrative & support | 2022 |
| Tibi Professional Builders Ltd | Construction | 2023 |
| Tibi Professional Cleaning Services Ltd | Administrative & support | 2023 |
| Tibin Ltd | Transport & logistics | 2025 |
| Tiffy Mechanical Services Ltd | Construction | 2025 |
| Tiger Home Solutions Ltd | Real estate | 2026 |
| Tiger Living Ltd | Real estate | 2021 |
| Tiger Specialist Access Ltd | Construction | 2020 |
| TIK Tutor Ltd | Professional & scientific | 2025 |
| Tiki Bar Boro Ltd | Hospitality | 2025 |
| Tikkaros North East Limited | Hospitality | 2025 |
| TIM Fleming Limited | Other services | 2014 |
| TIM Hunter Limited | Information & communication | 2021 |
| TIM Woodhouse Services Limited | Wholesale & retail | 2022 |
| Timeless Luxury Limited | Other services | 2025 |
| Timeless Touch Aesthetics AH Ltd | Other services | 2025 |
| Tison NE Ltd | Hospitality | 2025 |
| Titan Trailers Industries Limited | Manufacturing | 2011 |
| TJ NE Ltd | Other services | 2023 |
| Tjbrothers Limited | Wholesale & retail | 2025 |
| Tjlb Developments Limited | Real estate | 2024 |
| TJR Inspection Limited | Professional & scientific | 2015 |
| Tjtk Limited | Professional & scientific | 2024 |
| Tj’S Turbines Ltd | Construction | 2026 |
| TKS Car Mechanic Ltd | Wholesale & retail | 2025 |
| TL Networks Limited | Professional & scientific | 2018 |
| TLC Epoxy Flooring Ltd | Construction | 2026 |
| TLC Exteriors Ltd | Administrative & support | 2025 |
| Tlfa Limited | Transport & logistics | 1963 |
| TLY Trade Ltd | Wholesale & retail | 2022 |
| TM Leisure NE Limited | Hospitality | 2021 |
| TMC Garage Services Limited | Wholesale & retail | 2020 |