| T.G Roofing Oxfordshire Limited | Construction | 2025 |
| T.G.L Building Services Ltd | Construction | 2025 |
| T.J. Simmons & Company Ltd | Construction | 2002 |
| T.L Electrical Ltd | Construction | 2019 |
| TA Engineering Solutions Ltd | Manufacturing | 2016 |
| TAB Plumbing and Heating Ltd. | Construction | 2021 |
| Tablet Salt Direct Limited | Wholesale & retail | 2009 |
| Tabshift Limited | Information & communication | 2017 |
| TAC Collective Ltd | Professional & scientific | 2024 |
| TAC Construction Group Ltd | Construction | 2023 |
| Tacitus Consulting Ltd | Professional & scientific | 2000 |
| Tacklinginfertility Ltd | Health & social care | 2023 |
| Tactical Wireless Limited | Information & communication | 2013 |
| Tadano UK Ltd | Wholesale & retail | 2001 |
| Tadmarton Park Ltd | Real estate | 2023 |
| TAF Care Ltd | Health & social care | 2018 |
| Taffy's Grill Ltd | Hospitality | 2025 |
| Tahjatech Solutions Limited | Information & communication | 2008 |
| Tahlis Capital Ltd | Real estate | 2026 |
| Taho Ltd | Transport & logistics | 2017 |
| Tail-Crate Limited | Manufacturing | 2017 |
| Tailor Cutter Company Limited | Manufacturing | 2018 |
| Tailored Building Connections Ltd | Construction | 2019 |
| Tailored-Hr Ltd | Administrative & support | 2025 |
| Take 1 Finishes Ltd | Other services | 2015 |
| Talcarn Ltd | Professional & scientific | 2014 |
| Talesmith Limited | Information & communication | 2005 |
| Talk to ME CIC | Information & communication | 2025 |
| Tall MAN Solutions Ltd | Health & social care | 2016 |
| Tamarack Consulting Services Ltd | Information & communication | 2013 |
| Tamkel Limited | Information & communication | 2018 |
| Tandem TV & Film Limited | Information & communication | 1993 |
| Tang LOW Development Limited | Construction | 2013 |
| Tangled of Wendover Limited | Other services | 2016 |
| Tango Oscar Property Holdings Limited | Real estate | 2026 |
| Tani Management Limited | Real estate | 2025 |
| Tanno Traders Ltd | Hospitality | 2020 |
| Tapchat Limited | Information & communication | 2025 |
| Taplin Holdings Ltd | Financial services | 2024 |
| Taptap Limited | Professional & scientific | 2024 |
| Tara Recruitment Ltd | Administrative & support | 2023 |
| Tardis Communication Systems Ltd | Information & communication | 1994 |
| TAS Food Court Ltd | Hospitality | 2024 |
| Task 55 (Bucks) Ltd | Water & waste | 2025 |
| Task Consulting Ltd | Professional & scientific | 2014 |
| Taste of 1305 Ltd | Hospitality | 2024 |
| Taxmaze Limited | Professional & scientific | 2013 |
| Tayler Management Ltd | Arts & recreation | 2025 |
| Taylor Made Foresight Limited | Professional & scientific | 2025 |
| Taylormade Mana Ltd | Wholesale & retail | 2024 |
| TBJ Limited | Administrative & support | 2025 |
| TC Garden Rooms & Carpentry Ltd | Manufacturing | 2022 |
| Tchapman Realisations Limited | Wholesale & retail | 2025 |
| Tchen and Company Limited | Professional & scientific | 2006 |
| TD Gardens Ltd | Administrative & support | 2017 |
| Tea'D UP Limited | Wholesale & retail | 2025 |
| Team Awsum Ltd | Wholesale & retail | 2017 |
| Team First Key Ltd | Real estate | 2026 |
| Team Newbury Ltd | Hospitality | 2022 |
| Teamm Music Ltd | Information & communication | 2015 |
| Teams Solutions Ltd | Administrative & support | 2018 |
| Tech Ace Ltd. | Information & communication | 2011 |
| Tech Alarm Systems Limited | Administrative & support | 2019 |
| TECH123V Ltd | Wholesale & retail | 2024 |
| Techelect Ltd | Wholesale & retail | 2025 |
| Technique Media Limited | Information & communication | 2021 |
| Technology Base Aylesbury Limited | Wholesale & retail | 2023 |
| Technology Base Limited | Wholesale & retail | 2018 |
| Technoquestuk Limited | Information & communication | 2024 |
| Technosys Aisztec Limited | Information & communication | 2017 |
| Technovika Ltd | Information & communication | 2023 |
| Techooze Ltd | Information & communication | 2020 |
| Techtruck Transport Ltd | Transport & logistics | 2026 |
| Teide Engineering Services Limited | Professional & scientific | 2025 |
| Tekart Solutions Limited | Information & communication | 2019 |
| Tekir Wear Limited | Construction | 2022 |
| Tekwurx Holdings Limited | Financial services | 2018 |
| Tekwurx Limited | Information & communication | 2013 |
| Tekwurx Sales Limited | Information & communication | 2018 |
| Tekwurx Software Limited | Information & communication | 2013 |
| Telectica Ltd | Information & communication | 2012 |
| Temeraire Consulting Limited | Professional & scientific | 2015 |
| Temple Advice Service Ltd | Professional & scientific | 2015 |
| Temple Grenville Ltd | Professional & scientific | 2025 |
| Temple House Property Investments Ltd | Real estate | 2020 |
| Temple Legal Ltd | Professional & scientific | 2020 |
| Temple Square (Aylesbury) Ltd | Real estate | 2021 |
| Temple Square Investments Limited | Real estate | 2019 |
| Temple Street Holdings Limited | Financial services | 2020 |
| TEMPLE26 Services Limited | Real estate | 2021 |
| Tempo After Hours Ltd | Arts & recreation | 2025 |
| Tendi Choice Limited | Health & social care | 2026 |
| Tengar Land and Property Ltd | Financial services | 2025 |
| Tengiztek Limited | Other services | 2017 |
| Tenmela Limited | Transport & logistics | 2025 |
| Tennya Care Ltd | Health & social care | 2024 |
| Teqtonik Limited | Professional & scientific | 2010 |
| Teqzone Ltd | Other services | 2017 |
| Terminus Security Ltd | Extraterritorial | 2019 |
| Terra Sonic Ltd | Information & communication | 2024 |