| THE Travel Collective Ltd | Administrative & support | 2025 |
| THE Travel Experts International Ltd | Professional & scientific | 2013 |
| THE Tuning Fork Cafe Limited | Hospitality | 2016 |
| THE Vegetable Garden Ltd | Wholesale & retail | 2017 |
| THE Venue Group Holdings Ltd | Financial services | 2023 |
| THE Vine Inn Buckden Ltd | Hospitality | 2026 |
| THE Wafflers Rugby Ltd | Hospitality | 2024 |
| THE Weeks Print Consultancy Ltd. | Manufacturing | 2022 |
| THE Wildfire Pizza Company Ltd | Hospitality | 2017 |
| THE Woodhouse at Princethorpe Limited | Hospitality | 1988 |
| Theallsaints Ltd | Construction | 2017 |
| Theallsaints Property Management Ltd | Construction | 2026 |
| Theral Construction Limited | Construction | 2025 |
| Thercel Holdings Limited | Financial services | 2024 |
| Thercel Land Limited | Real estate | 2024 |
| Theurbanshire Ltd | Real estate | 2026 |
| Thingbling Ltd. | Wholesale & retail | 2013 |
| Think Through AI Ltd | Information & communication | 2026 |
| Thomas Anne Interiors Ltd | Manufacturing | 2019 |
| Thomas Brown Furnishings Ltd | Wholesale & retail | 2000 |
| Thomas Ford Construction Limited | Administrative & support | 2017 |
| Thomas Freelance Site Services Ltd | Administrative & support | 2024 |
| Thomas Property Management Limited | Real estate | 2022 |
| Thomson Trdd Limited | Professional & scientific | 2016 |
| Thor Retail Consultancy Ltd | Professional & scientific | 2018 |
| Thornton Robson LLP | | 2019 |
| Thoroughbred Associates Limited | Other services | 2014 |
| Thorpe Management Limited | Professional & scientific | 2003 |
| Thota Real Estates Ltd | Real estate | 2026 |
| Thoughtful Gestures Ltd | Wholesale & retail | 2024 |
| Three Chevrons Ltd | Manufacturing | 2008 |
| Three Counties Tutoring Limited | Education | 2019 |
| Three Lions Info Ltd | Information & communication | 2018 |
| Threeodore Limited | Information & communication | 2024 |
| Thriiive Consulting LLP | | 2011 |
| Thrive Management Ltd. | Professional & scientific | 2013 |
| Thrive Performance Gym Ltd | Arts & recreation | 2017 |
| Thrive Performance Personal Training Ltd | Arts & recreation | 2019 |
| Thundervine Limited | Professional & scientific | 2025 |
| Thurlaston Meadows Care Home Ltd. | Health & social care | 1993 |
| Thurnmill Autos Limited | Real estate | 2020 |
| Thwaites Commercial Properties Limited | Real estate | 2014 |
| Thwaites Developments Ltd. | Wholesale & retail | 2011 |
| Tibbsons Ltd | Real estate | 2024 |
| Tiberiu Cincu Transport Limited | Transport & logistics | 2019 |
| Tibor ORI Ltd | Transport & logistics | 2014 |
| Tiddlers Playschool Ltd | Education | 2019 |
| Tidytreasuresuk Ltd | Manufacturing | 2026 |
| Tiempo DE Lujo Ltd | Construction | 2019 |
| Tiger ROB Limited | Real estate | 2012 |
| Tiico Ltd | Information & communication | 2023 |
| Tilink(International) Limited | Transport & logistics | 2019 |
| Tilted Asset Management Limited | Real estate | 2016 |
| Timber Land SW Ltd | Wholesale & retail | 2024 |
| Timbers Carpentry Ltd | Construction | 2023 |
| Timbuktu Content Limited | Professional & scientific | 2017 |
| Time Transit Solutions Ltd | Transport & logistics | 2024 |
| Timms Homes Limited | Real estate | 2024 |
| Tinto Trading Limited | Other services | 2023 |
| Tir-Pawel Ltd | Transport & logistics | 2013 |
| Titan Building Developments Ltd | Construction | 2025 |
| Titan Construction and Building Services Ltd | Construction | 2023 |
| Titan Industries Limited | Professional & scientific | 2011 |
| TJ Homestay UK Ltd | Households | 2024 |
| TK Executive Travel Limited | Transport & logistics | 2018 |
| Tlet Professional Learning Limited | Education | 2014 |
| TLS 3 Ltd | Transport & logistics | 2018 |
| TM Estate Solutions Ltd | Construction | 2026 |
| TMA Transport Ltd | Transport & logistics | 2019 |
| TNA (UK) Limited | Transport & logistics | 2007 |
| Toad Group Ltd | Professional & scientific | 2025 |
| Toadhall Consultancy & Coaching Limited | Professional & scientific | 2018 |
| Tobias MSC Limited | Transport & logistics | 2017 |
| Toddle About West Northants Ltd | Information & communication | 2022 |
| Toft Farm Limited | Agriculture & fishing | 1997 |
| Toft Limited | Wholesale & retail | 2018 |
| Tofta Limited | Extraterritorial | 2018 |
| Tokenization Ltd | Wholesale & retail | 1990 |
| Tolak Medical Services Limited | Administrative & support | 2022 |
| TOM Gover Holdings Ltd | Real estate | 2018 |
| TOM Norman Design Limited | Other services | 2016 |
| TOM RAB Ltd | Transport & logistics | 2023 |
| TOM2YOU Ltd | Transport & logistics | 2020 |
| Tomasz Tomczak Ltd | Wholesale & retail | 2016 |
| Tomcraft Ltd | Transport & logistics | 2023 |
| Tomgandhi Consulting Limited | Information & communication | 2010 |
| Tommag Trans Ltd | Transport & logistics | 2014 |
| Toms Newsagents Limited | Wholesale & retail | 2008 |
| Tonga UK Ltd | Manufacturing | 2018 |
| Tonoah Ltd | Professional & scientific | 2017 |
| Tony and Yvonne Properties Limited | Real estate | 2019 |
| Tony Lester Auctions Limited | Wholesale & retail | 2010 |
| Tony's Trains at Barby Model Rail Ltd | Wholesale & retail | 2016 |
| Toolboxit Limited | Professional & scientific | 2017 |
| Toolsdown Ltd | Wholesale & retail | 2011 |
| Toor Wealth Management Ltd | Financial services | 2014 |
| Toorf Group Limited | Real estate | 2025 |
| Tooth & Nail Group Ltd | Professional & scientific | 2023 |
| Toothy Ltd | Financial services | 2025 |
| Top Chef 125 Limited | Hospitality | 2021 |