| THE Yorkshire & Humber Clinic Ltd | Professional & scientific | 2020 |
| THE Zoroastrian Trust Funds of Europe (Incorporated) | Health & social care | 1978 |
| THE “Amna Begum Community Welfare Trust” (Abcwt) | Health & social care | 2011 |
| The-Illy Ltd | Wholesale & retail | 2024 |
| The-Missing-Link.Info Limited | Information & communication | 2008 |
| The-Nu-Space Group Limited | Wholesale & retail | 2024 |
| The-Three-C Ltd | Construction | 2019 |
| THE1STPRINCIPLES Limited | Information & communication | 2022 |
| Thea Consultants Ltd | Administrative & support | 2014 |
| Thebe Logic Ltd | Information & communication | 2015 |
| Thebodymechanik Ltd | Professional & scientific | 2025 |
| Thecarcircle Ltd | Wholesale & retail | 2025 |
| Thechauffeurdrive.Com Limited | Transport & logistics | 2014 |
| Thecurator Ltd | Wholesale & retail | 2018 |
| Thedestination Limited | Administrative & support | 2025 |
| Thediamonddetailingco Ltd | Administrative & support | 2024 |
| Thefans Ltd. | Information & communication | 2017 |
| Thehumanworksco Limited | Professional & scientific | 2025 |
| Theis and Khan Architects Limited | Professional & scientific | 2002 |
| Thelb Ltd | Real estate | 2026 |
| Theme Properties Limited | Education | 1996 |
| Theme Services Limited | Education | 2004 |
| Themis EYE Ltd | Construction | 2012 |
| Themis Property Ltd | Real estate | 2024 |
| Themis Technologies Ltd | Information & communication | 2020 |
| Themusicnest Ltd | Education | 2025 |
| Theo & Levy Limited | Health & social care | 2025 |
| Theo Services Limited | Construction | 2015 |
| Theophania Ltd | Real estate | 2021 |
| Therapeutic Training Solutions Ltd | Administrative & support | 2022 |
| Therapy Tails CIC | Health & social care | 2025 |
| Theredbox Limited | Wholesale & retail | 2021 |
| Therefour UK Ltd | Information & communication | 2022 |
| Therightwayfba Ltd | Wholesale & retail | 2025 |
| Theriskpartners Limited | Administrative & support | 2019 |
| Thermal Glow Limited | Construction | 2020 |
| Thermaloft Insulation Limited | Construction | 2023 |
| Thermopanels Ltd | Wholesale & retail | 2026 |
| Therunawaychef Ltd | Wholesale & retail | 2026 |
| Thesend Ltd | Financial services | 2024 |
| Thesommofrock Ltd | Professional & scientific | 2026 |
| Theswana Ltd | Wholesale & retail | 2025 |
| Thetoothfairy Limited | Health & social care | 2012 |
| Theva Brothers Ltd | Real estate | 2019 |
| Theva Capital Ltd | Real estate | 2016 |
| Thevarasa Logistics Ltd | Transport & logistics | 2019 |
| Thevoguechic Ltd | Wholesale & retail | 2024 |
| Thin Space Uniforms Ltd | Administrative & support | 2019 |
| Thind Group Holdings Limited | Real estate | 2024 |
| Thind Subs Ltd | Hospitality | 2005 |
| Think Favours Ltd | Wholesale & retail | 2015 |
| Think Hotels Limited | Information & communication | 2011 |
| Think Mirror Mirror (Watford) Limited | Education | 2014 |
| Think Plus Software Ltd | Administrative & support | 2022 |
| Think Sketch Design Ltd | Professional & scientific | 2018 |
| Thinkerbox Limited | Information & communication | 2004 |
| Thinkin Limited | Professional & scientific | 2024 |
| Thinking Applications Ltd | Professional & scientific | 2021 |
| Thinking Choices Limited | Administrative & support | 2013 |
| Thinkit Technology Solutions Limited | Extraterritorial | 2018 |
| Third Flow Design Ltd | Information & communication | 2025 |
| Thirty Eight Blue Limited | Construction | 2016 |
| Thirty Nine Homes Ltd | Real estate | 2016 |
| Thirty One DVG (Management) Limited | Hospitality | 1997 |
| Thirty Seven WPR (Management) Limited | Hospitality | 2004 |
| Thiru Construction Ltd | Construction | 2023 |
| This Way Consulting Ltd | Administrative & support | 2020 |
| THJ Interiors Ltd | Administrative & support | 2017 |
| Thobani Frozen Foods Limited | Wholesale & retail | 1982 |
| Thomas & Thomas Contractors Limited | Construction | 2008 |
| Thomas Rattenbury Limited | Construction | 1989 |
| Thomaslev Construction Ltd | Construction | 2020 |
| Thompson & Baroni Architects Limited | Professional & scientific | 2003 |
| Thompson Mccabe Limited | Real estate | 2011 |
| Thompson Pinto Limited | Health & social care | 2023 |
| Thomwills Management Co Limited | Real estate | 2014 |
| Thornburrow Investment Limited | Real estate | 1992 |
| Thorndon Hall Management Company Limited | Households | 1979 |
| Thornstand Limited | Construction | 2015 |
| Thoucentric Limited | Information & communication | 2016 |
| Thpg Limited | Real estate | 2020 |
| Thread Apparel Limited | Wholesale & retail | 2025 |
| Thread ID Ltd | Information & communication | 2026 |
| Threads Collective Ltd | Wholesale & retail | 2024 |
| Three Bridges Australian Cobberdogs Limited | Agriculture & fishing | 2026 |
| Three D Club Harrow Ltd | Hospitality | 2025 |
| Three Kings Enterprise Ltd | Hospitality | 2013 |
| Three Knot Studios Limited | Information & communication | 2024 |
| Three Tigers Tattoo Ltd | Other services | 2024 |
| Three Trees Productions Limited | Construction | 2023 |
| Three Waters Limited | Health & social care | 2014 |
| Three Ways Consulting Ltd | Other services | 2015 |
| Three Ways Electrical Solutions Ltd | Construction | 2009 |
| THREE14 Online Ltd | Wholesale & retail | 2024 |
| Threedunes AI Limited | Information & communication | 2025 |
| Threeway Investments Limited | Real estate | 2009 |
| Thrisa Super Store Ltd | Wholesale & retail | 2020 |
| Thrishulam Limited | Professional & scientific | 1999 |
| Thriv Beverage Ltd | Wholesale & retail | 2025 |
| Thrive Business Club Limited | Other services | 2023 |