| Tolhurst Limited | Professional & scientific | 2005 |
| Tolyn & Co Properties Limited | Real estate | 2024 |
| Toma Capital Ltd | Health & social care | 2022 |
| Tomol Services Limited | Wholesale & retail | 2014 |
| Tony Nicklen Consultancy Services Ltd | Information & communication | 2025 |
| Tony Ockendon Fire Protection Limited | Professional & scientific | 2015 |
| TOO Marvellous Ltd | Wholesale & retail | 2013 |
| Tool Despatch Ltd | Wholesale & retail | 2013 |
| Top CUT Beauty Ltd | Other services | 2020 |
| Top Notch Car Hire Limited | Wholesale & retail | 2025 |
| Top Ranked Ltd | Information & communication | 2019 |
| Topicdrive Limited | Households | 1998 |
| Torcyte Ltd | Information & communication | 2026 |
| Tornado Digital Group Ltd | Information & communication | 2022 |
| Torneo Electric App Ltd | Transport & logistics | 2023 |
| Torneo Holdings Ltd | Wholesale & retail | 2019 |
| Torneo Limited | Transport & logistics | 2015 |
| Total Clarety Limited | Information & communication | 2021 |
| Total Football Development Ltd | Education | 2024 |
| Total Glazing Solutions Ltd | Construction | 2007 |
| Total Merchandise Group Limited | Financial services | 2023 |
| Totally Toy Clearance Limited | Wholesale & retail | 2012 |
| Touch Gloves Combat Academy Limited | Arts & recreation | 2025 |
| Touchbase MTC Limited | Administrative & support | 2010 |
| TOW Motorsport Ltd | Wholesale & retail | 2024 |
| Tower Heath Investments Limited | Administrative & support | 2005 |
| Towerfield Plating Limited | Manufacturing | 2008 |
| Townsend Place (Shrivenham) Management Company Limited | Households | 2018 |
| TPS Integrated Services Ltd | Professional & scientific | 2016 |
| Tracey Rowley Family Law & Mediation Limited | Professional & scientific | 2020 |
| Trademark Carpets Limited | Construction | 2012 |
| Traders World Limited | Wholesale & retail | 2022 |
| Tradesmartgb Ltd | Other services | 2015 |
| Trading Server Ltd | Financial services | 2020 |
| Trailer Marque Limited | Wholesale & retail | 2006 |
| Trailer UK Limited | Transport & logistics | 2006 |
| Tranquil Ventures Ltd | Financial services | 2024 |
| Tranquility Care and Consultancy Limited | Administrative & support | 2020 |
| Transline International Ltd | Transport & logistics | 2025 |
| Transport R US Limited | Transport & logistics | 2009 |
| Travelforce Limited | Hospitality | 2010 |
| Trawler Boyz Catering Ltd | Hospitality | 2023 |
| Trawler&Co Ltd | Professional & scientific | 2020 |
| Treacle and Toffee Limited | Wholesale & retail | 2011 |
| Treadzuk Ltd | Wholesale & retail | 2023 |
| Treats Hair & Beauty Ltd | Other services | 2016 |
| Trebor Restorations Ltd | Construction | 2011 |
| Tree of Life Networks Ltd. | Financial services | 2018 |
| Trem Fitness Limited | Arts & recreation | 2022 |
| Tremain Enterprises Ltd | Professional & scientific | 1998 |
| Tremlett Mews Ltd | Real estate | 2010 |
| Trendassist Company Limited | Real estate | 1993 |
| Trends Academy Ltd | Administrative & support | 2024 |
| Trends Lodge Ltd | Real estate | 2019 |
| Trendzstar Ltd | Wholesale & retail | 2025 |
| Tresus Group Limited | Construction | 2018 |
| Trialyst Group Ltd | Administrative & support | 2019 |
| Trinity 24 Limited | Health & social care | 2023 |
| Trinity International Management Limited | Hospitality | 2000 |
| Trinity People Limited | Education | 2003 |
| Trinitysoft Solutions Limited | Information & communication | 2012 |
| Trinket Box PRE School Ltd | Education | 2011 |
| Triple Shield Compliance Ltd | Construction | 2026 |
| Tristadeca Ltd | Information & communication | 2009 |
| Trivedi Limited | Construction | 2009 |
| Trivediproperties Ltd | Households | 2022 |
| Trix Medcare Ltd | Health & social care | 2016 |
| Trop-Hasi Ltd | Construction | 2023 |
| Trunker Ltd | Transport & logistics | 2026 |
| Trusted Traveller Limited | Information & communication | 2016 |
| TRY Fried N Grilled Chicken Ltd | Hospitality | 2025 |
| Très Doué Consulting Ltd | Construction | 2024 |
| TS Services Holdings Limited | Construction | 2021 |
| TSM Care Ltd | Health & social care | 2022 |
| Tsquare Living Limited | Hospitality | 2025 |
| Tuple Holdings Limited | Financial services | 2022 |
| Tuple Solutions Limited | Agriculture & fishing | 2015 |
| Turn Two Consultants Limited | Professional & scientific | 2025 |
| Turner Family Inns Ltd | Financial services | 2021 |
| Tuscany Limited | Other services | 2011 |
| TV and Telecoms Consulting Limited | Professional & scientific | 2014 |
| TW Express Logistics Ltd. | Transport & logistics | 2018 |
| Twelve Inches Pizza Ltd | Hospitality | 2021 |
| Twigworth Green Management Company Limited | Households | 2020 |
| Twin Roots Developments Limited | Construction | 2025 |
| Two Friends Barber Shop Limited | Other services | 2023 |
| Twoscope Limited | Information & communication | 2013 |
| Tybi.Ai Limited | Information & communication | 2025 |
| Tykon Connections Ltd | Hospitality | 2019 |
| U&J Traders & Services Ltd | Wholesale & retail | 2026 |
| U-Kind Enterprises Ltd | Wholesale & retail | 2020 |
| UBK (Thurloe) Limited | Extraterritorial | 2008 |
| UK Architectural Glass Ltd | Construction | 2014 |
| UK Business Doctor Limited | Information & communication | 2022 |
| UK Event Services Ltd | Other services | 2024 |
| UK Five Star Topsnails Ltd | Other services | 2024 |
| UK Group Services Ltd | Administrative & support | 2018 |
| UK Meica Ltd | Professional & scientific | 2022 |
| UK RAJ Properties Ltd | Real estate | 2026 |
| UK Solid Energy Limited | Professional & scientific | 2020 |