| THE Social Dough Company (Pinner) Ltd | Hospitality | 2022 |
| THE Social Dough Company (Ruislip) Ltd | Hospitality | 2025 |
| THE Social Dough Company Ltd | Hospitality | 2020 |
| THE Spinney (Northwood) Management Company Limited | Households | 2011 |
| THE Sports Sanctuary Limited | Wholesale & retail | 2018 |
| THE Sweet Loaf Club Ltd | Wholesale & retail | 2025 |
| THE Vintage Rooms Limited | Wholesale & retail | 2013 |
| THE Web Hubb Limited | Information & communication | 2019 |
| THE Well Group Limited | Water & waste | 2022 |
| THE Willow Rooms Limited | Other services | 2022 |
| Theale Surgery Limited | Health & social care | 2010 |
| Thearmours Limited | Households | 2010 |
| Thendral Mini Market Limited | Wholesale & retail | 2025 |
| Therapy Withinsight Limited | Administrative & support | 2017 |
| Thevendingco Ltd | Wholesale & retail | 2023 |
| Thirdway Investments Limited | Real estate | 2024 |
| Thirteen Large Limited | Administrative & support | 2005 |
| Thistlegorm Limited | Real estate | 2018 |
| THJ Properties Limited | Real estate | 2016 |
| Thomas Brown (Lettings) Limited | Real estate | 2010 |
| Thomas Brown (Management) Ltd | Extraterritorial | 2010 |
| Thomas Brown (Rickmansworth) Ltd | Real estate | 2009 |
| Thomas Brown Group Ltd | Extraterritorial | 2009 |
| Thornsdale Limited | Real estate | 2011 |
| Three Trees Ltd. | Information & communication | 1990 |
| Threeoeight Kilburn GP Limited | Real estate | 2013 |
| Threeoeight Kilburn Nominee Limited | Real estate | 2013 |
| Thrive Therapy Group Ltd | Health & social care | 2022 |
| Tidoa Ltd | Professional & scientific | 2018 |
| Tigma Limited | Real estate | 2009 |
| TIL Property Ltd | Households | 2022 |
| Timber and Build Company Limited | Wholesale & retail | 2025 |
| Time Film Limited | Information & communication | 2022 |
| Time for Productions Limited | Information & communication | 2026 |
| Time Travel & Tours Ltd | Transport & logistics | 2024 |
| Timecell Limited | Extraterritorial | 2005 |
| Timmi Property Limited | Real estate | 2023 |
| Tipworth Properties Limited | Real estate | 2000 |
| Titan SB Enterprises Limited | Wholesale & retail | 2025 |
| TLC Property Company (Northwood) Ltd | Real estate | 2012 |
| TNP Decorating & Building Ltd | Construction | 2021 |
| Tollumi Plant Hire UK Ltd | Water & waste | 2022 |
| Tomus Ltd | Construction | 2021 |
| Tony Wongs Limited | Hospitality | 2007 |
| Top Banana Events Limited | Arts & recreation | 1998 |
| Top Exports Limited | Wholesale & retail | 2003 |
| TOR Generics Limited | Wholesale & retail | 2002 |
| Torsten Brovang Limited | Administrative & support | 2009 |
| Tortie Hoare Limited | Manufacturing | 2016 |
| Total Health Therapy Ltd | Wholesale & retail | 2008 |
| Tottenham Lane Developments Limited | Construction | 2021 |
| Touch Wood Art Ltd | Wholesale & retail | 2025 |
| Townsends (Northwood) Limited | Real estate | 2015 |
| Toyvision Design Limited | Professional & scientific | 2016 |
| Toyvision Limited | Manufacturing | 1989 |
| Tradact Limited | Professional & scientific | 2013 |
| Trade Smart Car Sales Limited | Wholesale & retail | 2024 |
| Trade Valley Group Ltd | Information & communication | 2025 |
| Tradecraft Real Estate Limited | Real estate | 2023 |
| Traditional Wehera Aryuwedic Limited | Health & social care | 2026 |
| Transformation Partners Global Ltd | Administrative & support | 2024 |
| Transport House Development Limited | Construction | 2020 |
| Tras Holdings Ltd | Real estate | 2016 |
| Travel Inbound Limited | Transport & logistics | 2021 |
| Treasureheath Developments Limited | Real estate | 1987 |
| Treeform ARB Limited | Agriculture & fishing | 2024 |
| TRH Solutions Ltd | Wholesale & retail | 2023 |
| Trilok General Trading Limited | Wholesale & retail | 2021 |
| Trinity Close Residents Association Limited | Households | 1995 |
| Trip MAN Ltd | Wholesale & retail | 2014 |
| TRU Design and Build Ltd | Construction | 2016 |
| Trust in the Process Therapy Ltd | Health & social care | 2020 |
| Trustline Accounting Limited | Professional & scientific | 2021 |
| TSG 01 Ltd | Hospitality | 2025 |
| TSG 02 Ltd | Hospitality | 2025 |
| TT Revlis Ltd | Wholesale & retail | 2023 |
| Tudor Road Holdings Ltd | Real estate | 2016 |
| Turn Heads Global Ltd | Information & communication | 2025 |
| Turn Key Developments SW Ltd | Construction | 2021 |
| Turnberry Services Limited | Health & social care | 2008 |
| Tuxedo Accounting Ltd | Other services | 2026 |
| Twelve Private Members Clubs Limited | Arts & recreation | 2019 |
| Twin Cubs Ltd | Wholesale & retail | 2023 |
| Two Flying Fish Ltd | Information & communication | 2020 |
| Twomexicans Ltd | Hospitality | 2020 |
| Ugly Duck Limited | Professional & scientific | 2003 |
| UGO London Lifestyle Ltd | Wholesale & retail | 2019 |
| UK Carhouse Ltd | Wholesale & retail | 2018 |
| UK Construction Support Services Ltd. | Construction | 2013 |
| UK Property Networking Limited | Real estate | 2022 |
| Ukak Consultancy Ltd | Professional & scientific | 2020 |
| Ultimate Freedom Properties Limited | Real estate | 2020 |
| Ultra Performance Marketing Ltd | Information & communication | 2022 |
| Umash Marketing Limited | Manufacturing | 2008 |
| Undotted Ltd | Extraterritorial | 2022 |
| Unicorn Capital Limited | Administrative & support | 2009 |
| Unicorn City Limited | Hospitality | 2003 |
| Union Atelier Ltd | Manufacturing | 2023 |
| Unit 1 Stokenchurch Ltd | Real estate | 2024 |
| Unitara Property Management Ltd | Extraterritorial | 2015 |