| Tracks Investigations International CIC | Administrative & support | 2025 |
| Tracks Investigations Limited | Administrative & support | 2006 |
| Trade Wise 360 Limited | Construction | 2019 |
| Trade With Sawyer Limited | Financial services | 2024 |
| Tradenergy Limited | Professional & scientific | 2012 |
| TRADESPHERE1 UK Limited | Wholesale & retail | 2025 |
| Traditional Glaze Solutions Limited | Manufacturing | 2015 |
| Traduzz Limited | Information & communication | 2018 |
| Trafalgar Finance Limited | Real estate | 2021 |
| Trafford RD Ltd | Households | 2025 |
| Train 305 Limited | Arts & recreation | 2025 |
| Training and Research Support Centre Limited | Professional & scientific | 1999 |
| Tranquil Nimbus Ltd | Wholesale & retail | 2025 |
| Trans-Flooring Limited | Wholesale & retail | 2002 |
| Transform (Uganda) Limited | Education | 2008 |
| Transformation and Innovation Company Limited | Professional & scientific | 2025 |
| Transformational Health 4 Ltd | Arts & recreation | 2018 |
| Transfuga Limited | Financial services | 2020 |
| Transition by Design Cooperative CIC | Construction | 2015 |
| Transparency Access Partners Limited | Information & communication | 2025 |
| Transport Training Agency Limited | Transport & logistics | 2003 |
| Transun Flights Limited | Transport & logistics | 1996 |
| Transveza Ltd | Transport & logistics | 2014 |
| Tratratrax Ltd | Information & communication | 2023 |
| Trava Home Ltd | Real estate | 2022 |
| Trava Ltd | Wholesale & retail | 2021 |
| Travel Clubs World Ltd | Construction | 2006 |
| Travel Scholars Ltd | Administrative & support | 2022 |
| Travelora Ltd | Administrative & support | 2025 |
| Travelrs Ltd. | Information & communication | 2021 |
| Traxse Limited | Health & social care | 2014 |
| Treadwells SEO LAB Ltd | Professional & scientific | 2025 |
| Treasure Heritage Ltd | Wholesale & retail | 2025 |
| Treborg Care Ltd | Health & social care | 2012 |
| Tree Artisan Cafe Ltd | Hospitality | 2020 |
| Treedee Projects Ltd | Manufacturing | 2025 |
| Treescape Oxford Limited | Agriculture & fishing | 2011 |
| Treetop Solutions Limited | Information & communication | 2000 |
| Trending Trading Firm Ltd | Wholesale & retail | 2023 |
| Trenmile Limited | Hospitality | 2005 |
| Trentahyper Limited | Information & communication | 2000 |
| Trentwood Fencing Limited | Construction | 2013 |
| Trialex Ltd | Information & communication | 2022 |
| Tribela Ltd | Wholesale & retail | 2025 |
| Trienics Limited | Wholesale & retail | 2017 |
| Trifox Consult Ltd | Professional & scientific | 2024 |
| Trinakria Limited | Financial services | 2023 |
| Trinity College Developments Limited | Construction | 2004 |
| Trinity College Oxford Limited | Hospitality | 2007 |
| Trinity Fortune Group Ltd | Hospitality | 2026 |
| Trinity Management Services Limited | Professional & scientific | 2019 |
| Trinity Oxford Ball Committee Ltd | Hospitality | 2025 |
| Trinity Property Management Limited | Real estate | 2012 |
| Trinity Technology Limited | Information & communication | 2019 |
| Triple S Flex Ltd | Information & communication | 2022 |
| Tripp Hearing Limited | Health & social care | 2004 |
| Triquetra Education Ltd | Education | 2020 |
| Trish Knight Mortgage Solutions Ltd | Financial services | 2017 |
| Trishi Enterprise Limited | Hospitality | 2022 |
| Triskelion Limited | Real estate | 2018 |
| Trivet Restaurant Limited | Hospitality | 2017 |
| Trivium Estates Limited | Real estate | 2016 |
| Trocept Therapeutics Limited | Professional & scientific | 2020 |
| Troidajos Ltd | Hospitality | 2026 |
| Trojan Marine Engineering Ltd | Manufacturing | 2024 |
| Troll Tech Ltd | Information & communication | 2023 |
| Trost Ltd | Wholesale & retail | 2022 |
| Trouble & Fallowfield Holdings Ltd | Real estate | 2024 |
| Trout Investments Limited | Administrative & support | 2011 |
| Troy Customer Research Limited | Professional & scientific | 2003 |
| TRS Building Services Ltd | Construction | 2024 |
| Truck World Online Limited | Professional & scientific | 2016 |
| True Blue Architecture Ltd | Professional & scientific | 2022 |
| True Blue Consulting Limited | Information & communication | 2016 |
| Truecrest Property Group Ltd | Real estate | 2026 |
| Trueman Bailey Law Limited | Professional & scientific | 2025 |
| Trueman Entertainment Ltd | Hospitality | 2026 |
| Trueman Investments Ltd | Real estate | 2021 |
| Trueman's Solicitors Limited | Professional & scientific | 2018 |
| TSA Collective Ltd | Information & communication | 2024 |
| Tsarine Caviar UK Ltd | Manufacturing | 2021 |
| Tsdc Limited | Administrative & support | 2016 |
| TSE Noodle Ltd | Hospitality | 2020 |
| TSO Prestige Protection Ltd | Administrative & support | 2025 |
| Tsoy Developers Group Ltd | Administrative & support | 2016 |
| Tsoy Limited | Real estate | 2019 |
| Ttlg Ltd | Professional & scientific | 2014 |
| Ttoli Ltd | Construction | 2026 |
| TU Aesthetica Ltd | Other services | 2022 |
| Tuavista Ltd | Extraterritorial | 2007 |
| Tuckletts Limited | Other services | 2023 |
| Tuconcept Limited | Manufacturing | 2025 |
| Tuffcore Ltd | Arts & recreation | 2018 |
| Tukg Ltd | Wholesale & retail | 2025 |
| Tullsec Homes Ltd | Real estate | 2026 |
| Tully Monster Ltd | Information & communication | 2017 |
| Tumazo Pizza Limited | Hospitality | 2024 |
| Tupel Ltd | Manufacturing | 2012 |
| Tupel Research Ltd | Professional & scientific | 2023 |
| Turbo Boing Ltd | Information & communication | 2026 |