| THE Whitley Bay Treehouse Limited | Health & social care | 2009 |
| THE Yard Reclaimers Limited | Wholesale & retail | 2022 |
| Theniam Consultancy Ltd | Professional & scientific | 2024 |
| Therapeutic Recreational Experiences for Everyone (Tree) CIC | Health & social care | 2022 |
| Therapy North Ltd | Health & social care | 2024 |
| Thewlis RIG Inspection Services Ltd | Professional & scientific | 2023 |
| Thirlaway Project Management Ltd | Professional & scientific | 2021 |
| This IS Creative Enterprise C.I.C. | Education | 2013 |
| Thomas Heaton Limited | Information & communication | 2018 |
| Thomas Hedley and Sons Ltd | Construction | 2019 |
| Thomas Jennison Ltd | Construction | 2025 |
| Thomas Ridley Homes Limited | Real estate | 2024 |
| Thompson Art Shop Limited | Manufacturing | 2024 |
| Three Tonne Properties Limited | Real estate | 2021 |
| THREE60 Mapping Ltd | Professional & scientific | 2015 |
| Thurston's Foods Limited | Extraterritorial | 2014 |
| Tile UP Tile Down Ltd | Construction | 2023 |
| Tkette Ltd | Administrative & support | 2018 |
| TKM Medical Communications Ltd | Administrative & support | 2019 |
| Tldl Limited | Education | 2023 |
| TLW Solicitors Limited | Professional & scientific | 2013 |
| TMC Capital Ltd | Information & communication | 2011 |
| TMC Motorbikes Ltd | Wholesale & retail | 2025 |
| TMR2 Ltd | Hospitality | 2023 |
| Toby Geotechnical Limited | Construction | 2014 |
| Together Newcastle | Health & social care | 2012 |
| Together Transport Limited | Transport & logistics | 2024 |
| Tomeverington Fabrication Limited | Manufacturing | 2015 |
| Tony MK Ltd | Hospitality | 2018 |
| Top GIFT73 Limited | Wholesale & retail | 2024 |
| Top Line Promotions Limited | Real estate | 2004 |
| Top of the Glass Window Cleaning Ltd | Administrative & support | 2025 |
| Top Right Thinking Limited | Education | 2019 |
| Top Trimz Training Limited | Administrative & support | 2013 |
| Topp Holdings Ltd | Administrative & support | 2024 |
| Torbay Decorating Company Ltd. | Construction | 2001 |
| Total Foodservice Solutions Limited | Wholesale & retail | 2004 |
| Total Health and Performance CIC | Education | 2025 |
| Totallab Limited | Information & communication | 2007 |
| Town Wall Media Ltd | Professional & scientific | 2017 |
| Townshend Medical Limited | Health & social care | 2019 |
| Trade Tribe Limited | Information & communication | 2020 |
| Traditional Masonry Limited | Manufacturing | 2004 |
| Transparent Asset Solutions Ltd | Information & communication | 2025 |
| Traries Management and Consulting Limited | Professional & scientific | 2006 |
| Trauma Informed Community Action C.I.C. | Professional & scientific | 2024 |
| Trauma Medics Ltd | Health & social care | 2025 |
| Travel Editions Group Ltd | Administrative & support | 1994 |
| Travel Editions Purchases Limited | Administrative & support | 1996 |
| Traxx Music Ltd | Arts & recreation | 2020 |
| TRB the Roofing Brothers Ltd | Construction | 2026 |
| Treeview Properties Limited | Real estate | 2000 |
| Trespa U.K. Limited | Wholesale & retail | 1994 |
| Tress Labs Ltd | Information & communication | 2026 |
| TRI LIN (NE) Ltd | Hospitality | 2020 |
| Tria Kalamata Limited | Wholesale & retail | 2023 |
| Tria Services Limited | Households | 2023 |
| Tribe (Tynemouth) Limited | Wholesale & retail | 2016 |
| Trigo Wood Fired Pizza & Artisan Gelato Ltd | Hospitality | 2025 |
| Trinity Precision Engineering (Holdings) Limited | Professional & scientific | 2018 |
| Trinity Precision Engineering Ltd | Manufacturing | 2013 |
| Trinity Rentals Limited | Administrative & support | 2018 |
| Trolight Ltd | Professional & scientific | 2024 |
| TRT Movement Limited | Wholesale & retail | 2026 |
| True North East Services Ltd | Administrative & support | 2026 |
| True North Social Ltd | Professional & scientific | 2023 |
| Trust KB Consulting Limited | Professional & scientific | 2025 |
| Trust KB2 Limited | Financial services | 2013 |
| TS Wind Ltd | Administrative & support | 2022 |
| TT Group NE Limited | Financial services | 2025 |
| TT Properties NE Ltd | Real estate | 2025 |
| TTP Entertainment Ltd | Hospitality | 2021 |
| Tulles and Wools Ltd | Wholesale & retail | 2021 |
| Tulloch Torque Ltd | Energy | 2017 |
| Tumble Gymnastics and Activity Centre CIC | Arts & recreation | 2018 |
| Turkish Barber Top CUT Ltd | Other services | 2025 |
| Turner & Wrights Limited | Wholesale & retail | 1996 |
| Turps Film Limited | Information & communication | 2021 |
| Turton Property Ltd | Real estate | 2025 |
| Tutti & Co (N.E.) Limited | Wholesale & retail | 2007 |
| TW Wright Services Ltd | Construction | 2025 |
| TWELVE25 Ltd | Hospitality | 2020 |
| Twin Volt Electricals Limited | Construction | 2024 |
| Tyne Audio Ltd | Administrative & support | 2020 |
| Tyne Bridge Decorators Limited | Construction | 2026 |
| Tyne Cabins and Lodges Northumberland Limited | Hospitality | 2020 |
| Tyne Cruises Limited | Education | 2026 |
| Tyne Escapes Ltd | Real estate | 2026 |
| Tyne House Limited | Hospitality | 2023 |
| Tyne Insulation Supplies Limited | Wholesale & retail | 1987 |
| Tyne Plastics Limited | Wholesale & retail | 2012 |
| Tyne Properties ( North East ) Limited | Real estate | 2020 |
| Tyne Properties Limited | Real estate | 1999 |
| Tyne Rope Access Ltd | Other services | 2019 |
| Tyne Tees Fasteners (North East) Ltd | Wholesale & retail | 2015 |
| Tyne to Summit CIC | Administrative & support | 2024 |
| Tyne Tyres Auto Centre Limited | Wholesale & retail | 2002 |
| Tynebase Ltd | Information & communication | 2026 |
| Tynehealth Limited | Health & social care | 2006 |
| Tyneheart Psychology Counselling & Psychotherapy Limited | Education | 2023 |