| Thistle&Bloom Ltd | Wholesale & retail | 2025 |
| Thistledown Homes Ltd | Real estate | 2020 |
| Thobes of Sultan Ltd | Wholesale & retail | 2026 |
| Thomas & Young Rural Assets Limited | Real estate | 2025 |
| Thomas & Young Wealth Management Ltd | Professional & scientific | 2014 |
| Thomas Broadhurst Ltd | Extraterritorial | 2023 |
| Thomas Peatling Ltd | Wholesale & retail | 2000 |
| Thomas William Broadhurst Limited | Extraterritorial | 2023 |
| Thomascare Recruitment Agency Ltd | Hospitality | 2017 |
| Thompson Electrical Services Training Limited | Education | 2009 |
| Thompson Training Ltd | Education | 2008 |
| Thorley Close Management Company Limited | Households | 2015 |
| Thorne Farriery Ltd | Professional & scientific | 2022 |
| Thornit Canker Ltd. | Manufacturing | 2012 |
| Thornton Construction Limited | Construction | 2015 |
| Thornton Event Properties Limited | Real estate | 2023 |
| Thornton Park Associates Ltd | Professional & scientific | 2016 |
| Thoroughbred Contracts Ltd | Wholesale & retail | 2008 |
| Thoroughbred Industrial Doors (Royston) Limited | Construction | 2011 |
| Thorp Property Limited | Real estate | 2022 |
| Thos. H. Bretton Limited | Manufacturing | 1998 |
| Threadjester Ltd | Manufacturing | 2023 |
| Three Geese Collective Ltd | Arts & recreation | 2024 |
| Three MAN Rocket Limited | Extraterritorial | 2015 |
| Three Ohenes Digital Media Ltd | Hospitality | 2020 |
| Three PIN Productions Ltd. | Arts & recreation | 2012 |
| Three Puppy Fashion Ltd | Wholesale & retail | 2025 |
| Three Saints Engineering Services Ltd | Administrative & support | 2010 |
| THREE8ONE Group Ltd | Real estate | 2026 |
| Threefolds Global Limited | Wholesale & retail | 2024 |
| Thrills Ventures Limited | Wholesale & retail | 2024 |
| Thrive Child and Youth Support Services Ltd | Public administration | 2025 |
| Thrive Fit UK - Outdoor Bootcamps Ltd | Arts & recreation | 2025 |
| Thrive Wealth Club Ltd | Other services | 2026 |
| Thriverton Ltd | Wholesale & retail | 2024 |
| Thruftnell Ltd | Wholesale & retail | 2026 |
| Thurlow Resource Solutions Ltd | Administrative & support | 2015 |
| Thurston Building Supplies Limited | Administrative & support | 1998 |
| Thurston Butchers Limited | Manufacturing | 2016 |
| Thurston FOX & Hounds Limited | Hospitality | 2008 |
| Thurston Granary Limited | Real estate | 2020 |
| Thurston Pre-School Limited | Education | 2011 |
| Thurston Victoria PUB Co Ltd | Hospitality | 2025 |
| Thynora Ltd | Wholesale & retail | 2025 |
| Tianna Beauty Ltd | Other services | 2021 |
| Tiay Consultancy Ltd | Other services | 2021 |
| TIB Property Investments Ltd | Hospitality | 2023 |
| Tibitisha Holdings Limited | Real estate | 2023 |
| Ticey DEE Ltd | Real estate | 2024 |
| Tickbox Solutions Limited | Professional & scientific | 2025 |
| Tickle ME Pink Group Ltd | Wholesale & retail | 2021 |
| Tide Construction Consultancy Limited | Professional & scientific | 2026 |
| Tidy Scape Cleaning Services Ltd | Construction | 2023 |
| Tidy Tigs Limited | Administrative & support | 2017 |
| Tidy Touch Cleaning Ltd | Administrative & support | 2025 |
| Tifer Limited | Information & communication | 2013 |
| Tiffany Jones Holdings Ltd | Financial services | 2025 |
| Tiffany Jones Property Holdings Ltd | Real estate | 2023 |
| Tiffany Jones Property Management Ltd | Real estate | 2024 |
| Tiffany O’Neill Therapy and Assessment Ltd | Health & social care | 2022 |
| Tiffanycoofnewyork Limited | Wholesale & retail | 2025 |
| Tiffin's Tea & Coffee House Ltd | Hospitality | 2017 |
| Tigerlily Marketing Ltd | Professional & scientific | 2025 |
| Tigertree Solutions Ltd | Professional & scientific | 2024 |
| Tignum Construction Ltd | Manufacturing | 2025 |
| Tigris Laboratories Ltd | Administrative & support | 2020 |
| Tigrisk Ltd | Real estate | 2024 |
| Tike E-Commerce Ltd | Wholesale & retail | 2026 |
| Tilbrook's Landscape Limited | Administrative & support | 1974 |
| Tilbury Project Services Ltd | Real estate | 2018 |
| Tiller (Badwell ASH) Ltd | Construction | 2024 |
| Tiller (Charsfield) Ltd | Construction | 2024 |
| Tiller (Orford) Ltd | Construction | 2020 |
| Tilley & Stewart Holdings Ltd | Financial services | 2025 |
| Till’S Handyman Services Ltd | Administrative & support | 2025 |
| TIM Bishop Consulting Limited | Professional & scientific | 2006 |
| TIM Hayes Limited | Extraterritorial | 2023 |
| TIM Mendes DA Costa Holdings Limited | Financial services | 2022 |
| TIM Mendes DA Costa Limited | Other services | 2019 |
| TIM Property Limited | Real estate | 2006 |
| TIM Vorster LLP | | 2011 |
| Timber Force Limited | Administrative & support | 2016 |
| Timber Frame Jobs Ltd | Administrative & support | 2007 |
| Time OUT Support Services Limited | Other services | 2021 |
| Timedot Ltd | Manufacturing | 2023 |
| Timeline Consultancy Limited | Professional & scientific | 2024 |
| Timetoventures Limited | Information & communication | 2017 |
| Timetrak Limited | Information & communication | 2023 |
| Timi Tims Ltd | Professional & scientific | 2018 |
| Timi Tims Properties Ltd | Real estate | 2022 |
| Timothy Rose Properties Ltd | Real estate | 2023 |
| Tingle Pleasure Ltd | Other services | 2025 |
| Tinieai Ltd | Information & communication | 2024 |
| Tinkertrinket Ltd | Wholesale & retail | 2025 |
| Tinroof Communications Limited | Professional & scientific | 2024 |
| Tiny Ortho Limited | Health & social care | 2014 |
| TIP Top Roofing and Building Ltd | Construction | 2025 |
| Tipmate Solutions Ltd | Information & communication | 2026 |
| Tipper Team Limited | Transport & logistics | 2018 |
| Tipperlink Ltd | Transport & logistics | 2026 |