| THE Shambles Bar Ltd | Wholesale & retail | 2023 |
| THE Skin Psychologist Ltd | Health & social care | 2023 |
| THE Specialist Washing Company Limited | Manufacturing | 2007 |
| THE ST James Gallery Limited | Construction | 2016 |
| THE Story Business Limited | Professional & scientific | 2014 |
| THE Style Edit Limited | Wholesale & retail | 2026 |
| THE Sushiko Ltd | Hospitality | 2025 |
| THE Talent Resource Limited | Administrative & support | 2008 |
| THE Telos Foundation | Professional & scientific | 2008 |
| THE Tiny Agency Ltd | Professional & scientific | 2011 |
| THE Transport Brothers Ltd | Transport & logistics | 2025 |
| THE Tutoring Club Limited | Education | 2026 |
| THE United Workplace Limited | Other services | 2016 |
| THE Walled Garden Kingham Ltd | Households | 2024 |
| THE Waterfront (Thames Side) Management Company Limited | Households | 2017 |
| THE Wealth Forums Limited | Information & communication | 2016 |
| THE White Orchid Limited | Other services | 2003 |
| THE Wholesome Crunch Co. Limited | Manufacturing | 2019 |
| THE Window Seat Guide Ltd | Information & communication | 2019 |
| THE Windsor House Ltd | Administrative & support | 2005 |
| THE Windsor Leadership Trust | Education | 1995 |
| THE Windsor Psychologist Limited | Health & social care | 2021 |
| THE Windsor Wellness Clinic LLP | | 2024 |
| THE Woodlarks Management Company Limited | Households | 2020 |
| THE Word Wheel Ltd | Administrative & support | 2014 |
| THE World Ship Society Limited | Other services | 2002 |
| THE Yellow BAG Company Limited | Professional & scientific | 2012 |
| THE Yews Investment Company Ltd | Financial services | 2017 |
| Thecleangroup Limited | Administrative & support | 2024 |
| Thecodesaiyan Ltd | Wholesale & retail | 2025 |
| Thenextround, Inc.-Eafe Ltd. | | 2007 |
| Theorycraft Labs Limited | Manufacturing | 2026 |
| Theranostic Imaging Ltd | Financial services | 2012 |
| Thermal Ceramics Limited | Professional & scientific | 1976 |
| Thewholesalesuppliers Ltd | Wholesale & retail | 2021 |
| Think Tall Limited | Construction | 2023 |
| Thinklateral Limited | Information & communication | 2003 |
| Third Down Ltd | Professional & scientific | 2021 |
| Third Planet Limited | Professional & scientific | 2023 |
| Third Rochford (Slough) Management Company Limited | Households | 2020 |
| Thirlmere Financial Ltd | Information & communication | 2016 |
| Thirty Cosmetics Ltd | Wholesale & retail | 2025 |
| Thomae Compass Ltd | Information & communication | 2026 |
| Thomas Smith Heating and GAS Limited | Construction | 2020 |
| Thomas Sword Limited | Information & communication | 2020 |
| Thompson & Tails Ltd | Professional & scientific | 2022 |
| Thomson House RTM Company Limited | Real estate | 2018 |
| Thorney Farm Developments Limited | Real estate | 1994 |
| Thorney Farm Estates Limited | Extraterritorial | 2014 |
| Thorney Farm Properties Limited | Real estate | 2014 |
| Thornwray Developments Limited | Construction | 2018 |
| Threaded Landscapes Ltd | Professional & scientific | 2024 |
| Three Dots Lettings Ltd | Real estate | 2023 |
| Three Kings Accounting Ltd | Professional & scientific | 2007 |
| Three Oaks Property Alliance Ltd | Real estate | 2024 |
| Three Peaks Learning Design Limited | Education | 2025 |
| Thrive to Achieve Limited | Professional & scientific | 2023 |
| Thtenn Ltd | Administrative & support | 2025 |
| Thula Africa Ltd | Wholesale & retail | 2023 |
| Thula SEO Ltd | Information & communication | 2024 |
| Tibout Pets Limited | Other services | 2018 |
| Tied UP B Limited | Manufacturing | 2018 |
| Tigers PAD Restaurant Limited | Hospitality | 2009 |
| Tilbury Lodge (South Croydon) Management Company Limited | Households | 2019 |
| Tiles Italia Ltd | Wholesale & retail | 2021 |
| Time Watch Repair.Arc Limited | Other services | 2024 |
| Time Watch Repair.W Limited | Other services | 2024 |
| Tiny Wells Limited | Real estate | 2025 |
| Tiola Ltd | Other services | 2025 |
| TIP Top Mortgages Ltd | Financial services | 2025 |
| Titan Demolition Limited | Construction | 2020 |
| Titan Group Holdings Limited | Financial services | 2020 |
| Tithe Court Residents Management Co. Limited | Households | 1972 |
| Tivaam Ltd | Health & social care | 2014 |
| TJL Assessments Ltd | Professional & scientific | 2016 |
| TK Number 5 Limited | Hospitality | 2014 |
| TKL Nails Ltd | Other services | 2021 |
| Tlcare UK Ltd | Health & social care | 2008 |
| TM Nicholson Consulting Limited | Professional & scientific | 2023 |
| TM Props Limited | Administrative & support | 2022 |
| TMS R US Ltd | Professional & scientific | 2025 |
| TOA Group Investments Limited | Professional & scientific | 2025 |
| Toddlecare Nurseries Ltd | Health & social care | 2024 |
| TOM Neill Ltd | Arts & recreation | 2019 |
| TOM Nutter Scholarships Ltd | Arts & recreation | 2017 |
| Tomkatis Ltd | Wholesale & retail | 2025 |
| Tomorrow's Company (Enterprises) Limited | Professional & scientific | 1995 |
| Top Notch Roofing Experts Limited | Construction | 2025 |
| Top Tier Leads Limited | Professional & scientific | 2025 |
| TOPCAT5 Ltd | Real estate | 2003 |
| Torunlar Property Investments Limited | Real estate | 2025 |
| Toscana Restaurant & Bar Limited | Hospitality | 2025 |
| Total Sprays Limited | Construction | 2018 |
| Tothills Launderers and DRY Cleaners Limited | Other services | 2015 |
| Touch of Pinks Ltd | Other services | 2024 |
| Towergate (Uxbridge) Management Company Limited | Households | 1999 |
| Towers Environmental Limited | Construction | 2019 |
| TPW Consultancy Limited | Administrative & support | 2007 |
| Trackster Ltd | Information & communication | 2017 |
| Trading 25 Ltd | Real estate | 2025 |