| Tranquillity Through Mindfulness Community Interest Company | Health & social care | 2020 |
| Transformative Change Management Solutions Ltd | Professional & scientific | 2025 |
| Trash Taxis Ltd | Water & waste | 2018 |
| Travel Patches Ltd | Wholesale & retail | 2023 |
| Travelglobeadventures Ltd | Administrative & support | 2025 |
| Treadmill Gym Ltd | Arts & recreation | 2014 |
| Treblif Limited | Health & social care | 2024 |
| Trends 7 Eleven UK Ltd. | Wholesale & retail | 2010 |
| Trewick Limited | Construction | 2026 |
| Tri-B Projects Limited | Construction | 2018 |
| Trident Surveying Ltd | Professional & scientific | 2006 |
| Triform Digital Limited | Information & communication | 2025 |
| Trignomix Ltd | Information & communication | 1999 |
| Trimline Systems (NE) Ltd | Wholesale & retail | 2014 |
| Trinity Leisure Limited | Hospitality | 2024 |
| Trinity Oaks Limited | Wholesale & retail | 2019 |
| Trio G Investments Ltd | Real estate | 2019 |
| Tripe Factory Sunderland Limited | Manufacturing | 2021 |
| Triple a and E Radientt Limited | Professional & scientific | 2024 |
| Triple a Barbers Ltd | Other services | 2025 |
| Triple B Barber Ltd | Other services | 2026 |
| Triple B1 Barber Ltd | Other services | 2024 |
| Triple C Barbers Ltd | Other services | 2026 |
| Triple Feast Limited | Hospitality | 2025 |
| Tripple F Group Ltd | Wholesale & retail | 2026 |
| Trirett Ltd | Households | 2025 |
| Trisk Property Ltd | Real estate | 2024 |
| Triune Dynamics Limited | Information & communication | 2025 |
| Trivista Homes Ltd | Real estate | 2025 |
| TRK Building Services Limited | Construction | 2025 |
| Trojan Leisure Ltd | Other services | 2020 |
| Troo Ltd | Other services | 2016 |
| Tropical Hair & Beauty by Nichol Ltd | Other services | 2021 |
| True Hospitality Ltd | Hospitality | 2026 |
| True Radiance Aesthetics Ltd | Health & social care | 2026 |
| Truewind Blade Repair Ltd | Manufacturing | 2026 |
| Trufl Ltd | Extraterritorial | 2020 |
| Trust Print Consultants Limited | Manufacturing | 2011 |
| Trusted Package Company Ltd | Administrative & support | 2020 |
| Trusted Trade Tech Limited | Manufacturing | 2025 |
| Trusteeco (UK) Ltd | Financial services | 2014 |
| TRY New Things CIC | Arts & recreation | 2024 |
| TSA Family UK Ltd | Wholesale & retail | 2022 |
| TSD PLG Ltd | Hospitality | 2025 |
| TSF Healthcare Solutions Limited | Administrative & support | 2023 |
| TSG Advertising Ltd | Professional & scientific | 2024 |
| Tshaanth Limited | Wholesale & retail | 2021 |
| Tsmc Consultancy Limited | Arts & recreation | 2022 |
| TT Pizza Ltd | Hospitality | 2024 |
| TT Sunderland Limited | Hospitality | 2023 |
| TTM North East Limited | Construction | 2018 |
| Ttonic Limited | Hospitality | 2024 |
| TTR Barnes Audit Limited | Professional & scientific | 2020 |
| Ttrb Limited | Professional & scientific | 2009 |
| Tudhoe Pizzeria Ltd | Hospitality | 2017 |
| Tudor House Maintenance Limited | Construction | 2005 |
| TUF Wear Ltd | Wholesale & retail | 2010 |
| Tuffy & Co Coffee Ltd | Hospitality | 2024 |
| Tufts International Services Ltd | Professional & scientific | 2026 |
| Tumbles World Ltd | Hospitality | 2018 |
| Tunnel Consultants Services Limited | Construction | 2002 |
| Tunstall Allotments 2021 Ltd | Agriculture & fishing | 2021 |
| Tunstall Developments Limited | Construction | 2008 |
| Tunstall Electrics Ltd | Construction | 2015 |
| Turitrade Ltd | Wholesale & retail | 2026 |
| Turnbull Investments NE Limited | Transport & logistics | 2020 |
| Tutor Trend Ltd | Wholesale & retail | 2024 |
| TW Brickwork Ltd | Construction | 2026 |
| Twenty Ninety Nine Ltd | Real estate | 2021 |
| Twenty-Eight 28 Group Limited | Real estate | 2024 |
| Twenty-Eight 28 Property Limited | Construction | 2024 |
| Twfrs Limited | Public administration | 2014 |
| Twilight Ecology Limited | Professional & scientific | 2022 |
| Twilighttraders Limited | Wholesale & retail | 2021 |
| TWR Group Limited | Manufacturing | 2011 |
| TWR UK Holdings Ltd | Professional & scientific | 2005 |
| TY Image Limited | Information & communication | 2024 |
| Tybre Associates Ltd | Wholesale & retail | 2025 |
| Tydra Ltd | Wholesale & retail | 2024 |
| Tyne & Wear Furnishings Ltd | Wholesale & retail | 2017 |
| Tyne & Wear Joinery Ltd | Construction | 2024 |
| Tyne & Wear Paving & Landscaping Ltd | Administrative & support | 2025 |
| Tyne & Wear Properties Ltd | Real estate | 1988 |
| Tyne and Wear Engineering Co. Limited | Manufacturing | 1978 |
| Tyne and Wear Fire and Rescue Service Sports and Welfare Club Limited | Education | 2021 |
| Tyne and Wear Homes Ltd | Construction | 2026 |
| Tyne and Wear Installations (GAS) Ltd | Construction | 2026 |
| Tyne and Wear Installations Ltd | Construction | 2026 |
| Tyne and Wear Plastering Ltd | Construction | 2019 |
| Tyne College | Education | 2024 |
| Tyne Developers Limited | Construction | 2025 |
| Tyne Holdings Limited | Professional & scientific | 2024 |
| Tyne N Wear Installations Ltd | Construction | 2024 |
| Tyne Tees Publishing Ltd | Information & communication | 2018 |
| Tyne Tubes Limited | Manufacturing | 2005 |
| Tyneside Blast Cleaning & Painting Limited | Construction | 2020 |
| Tyneside Motor Company Limited | Wholesale & retail | 2017 |
| Tyneside Property Developments Limited | Real estate | 1960 |
| Tynewood Limited | Extraterritorial | 1998 |
| U&G Global Education Limited | Professional & scientific | 2026 |