| Trenear Close RTM Company Limited | Households | 2009 |
| Trevora Enterprises Ltd | Wholesale & retail | 2024 |
| Trial Talent Plus Ltd | Administrative & support | 2025 |
| Trigger Direct Limited | Agriculture & fishing | 2000 |
| Trim and Bleed Limited | Information & communication | 2014 |
| Trimbio Ltd | Professional & scientific | 2013 |
| Trinity Building Contractors Ltd | Professional & scientific | 2022 |
| Trinity Stack Ltd | Information & communication | 2019 |
| Triple Dash Limited | Information & communication | 2025 |
| Tripsure Group Ltd | Financial services | 2003 |
| Trish Glancy Mindset Mastery Ltd | Other services | 2017 |
| Trison Consulting Limited | Professional & scientific | 2025 |
| Tristar Computing Ltd | Information & communication | 2004 |
| Tritel Communications Limited | Information & communication | 1997 |
| Trojan Household Clearance Ltd | Water & waste | 2022 |
| Trout Tickler Enterprises Limited | Professional & scientific | 2009 |
| Trovr Tech Ltd | Information & communication | 2022 |
| TRU English Bespoke Joinery Ltd | Construction | 2016 |
| Truck and Commercial Repairs Limited | Wholesale & retail | 2012 |
| True North Asset Holdings Limited | Real estate | 2025 |
| True Project Developments Limited | Construction | 2024 |
| True Roots Therapy Ltd | Education | 2025 |
| True Shine Car Wash Ltd | Wholesale & retail | 2024 |
| True Upholstery Ltd | Administrative & support | 2017 |
| Truest Fitness Limited | Wholesale & retail | 2024 |
| Truetemp Hvac Ltd | Construction | 2025 |
| Trupulse Media Limited | Professional & scientific | 2025 |
| Trust Health Limited | Administrative & support | 2006 |
| TT Consulting Sussex Limited | Professional & scientific | 2018 |
| TT VIP Ltd | Transport & logistics | 2019 |
| TTC - Total Tree Care Ltd | Agriculture & fishing | 2018 |
| TTM Investments Limited | Real estate | 2009 |
| TTS Health Group Ltd | Health & social care | 2019 |
| Tubstore Leisure Ltd | Wholesale & retail | 2019 |
| Tubular Scaffolding Construction Limited | Construction | 2014 |
| Tudor Manor Investments Limited | Real estate | 2013 |
| TUK TUK Horsham Ltd | Hospitality | 2022 |
| Tully Lyell Collective Limited | Financial services | 2026 |
| Tulpin Group (UK) Limited | Transport & logistics | 2024 |
| Tundry Construction Ltd | Construction | 2015 |
| Turkuaz Horsham Limited | Real estate | 2021 |
| Turn This UP Music Ltd | Information & communication | 2025 |
| Turner Security Systems Limited | Administrative & support | 2000 |
| Turners Electrical Ltd | Construction | 2014 |
| Turners Removals (Sussex) Ltd | Transport & logistics | 2011 |
| Turtle Dove Communications Ltd | Administrative & support | 2017 |
| TW Creative Limited | Extraterritorial | 2015 |
| Twelve Eighteen Estates Ltd | Real estate | 2022 |
| Twelve Four Limited | Hospitality | 2023 |
| Twenty Two Ventures Limited | Professional & scientific | 2022 |
| TWENTY20 Software Limited | Information & communication | 2020 |
| Twin Haulage Ltd | Transport & logistics | 2022 |
| Twinn Media Limited | Professional & scientific | 2025 |
| Twix Store Ltd | Wholesale & retail | 2024 |
| Two and Four Precision Bodyworks Limited | Wholesale & retail | 2025 |
| TY Glyn Student (One) Limited | Real estate | 2014 |
| TY Glyn Student Ltd | Construction | 2011 |
| Tyburn Consulting Limited | Construction | 2014 |
| TYE Aerospace Services Limited | Professional & scientific | 1998 |
| Tyler Charles Ltd | Administrative & support | 2016 |
| Tymperley Court (Horsham) Managements Limited | Households | 1997 |
| Tyrefix Pros Group Limited | Wholesale & retail | 2025 |
| Tyson Boxes Ltd | Manufacturing | 2003 |
| Tyson Limited | Wholesale & retail | 2003 |
| Tyson-Davies Restoration Ltd | Water & waste | 2002 |
| T’Imole Limited | Manufacturing | 2026 |
| U'N'Ity Removals Ltd | Transport & logistics | 2026 |
| U.K. Machine Tools Ltd | Manufacturing | 2003 |
| Uberwulf Limited | Information & communication | 2020 |
| Ugarit Music Ltd | Information & communication | 2021 |
| Uhambo Ltd | Hospitality | 2019 |
| UK Address Ltd | Real estate | 2015 |
| UK Catering Supplies LLP | | 2021 |
| UK Construction & Renovation Limited | Construction | 2023 |
| UK Fabric Shows Limited | Other services | 2019 |
| UK Generating-Set & CHP Association | Other services | 2023 |
| UK Inter Web Limited | Information & communication | 2000 |
| UK Intertrade Ltd | Wholesale & retail | 2020 |
| UK Shredding Ltd | Water & waste | 2025 |
| UK Site Sourcing Ltd | Real estate | 2026 |
| UK Snagging Inspections Ltd | Construction | 2021 |
| UK Squared Ltd | Professional & scientific | 2026 |
| UK Turnstiles Limited | Administrative & support | 2023 |
| UK Waves Ltd | Wholesale & retail | 2019 |
| Uk&D Technical Service Ltd | Professional & scientific | 2025 |
| Uksynergy Property Ltd | Real estate | 2020 |
| Ultima Testing Limited | Information & communication | 2011 |
| Ultimate Autocare Limited | Wholesale & retail | 2016 |
| Ultimate Goal Ltd | Information & communication | 1998 |
| Unbound Women Ltd | Wholesale & retail | 2024 |
| Under and Over Groundwork and Civil Engineering Ltd | Administrative & support | 2013 |
| Undercover Woodland Escape Ltd | Hospitality | 2020 |
| Underscore Group Ltd | Professional & scientific | 2016 |
| Unicom Consultancy Limited | Information & communication | 2017 |
| Union Castle Limited | Real estate | 2000 |
| Union Home & Lifestyle Ltd | Wholesale & retail | 2019 |
| Unipoint International Limited | Professional & scientific | 1989 |
| Unique Fashion (London) Ltd | Other services | 2021 |
| Unique Financial Planning Limited | Financial services | 2014 |
| United Hygiene Solutions Limited | Administrative & support | 1993 |