| Theaker & Scott Limited | Other services | 2022 |
| Theatre at Waterfall Limited | Professional & scientific | 2010 |
| Thebestpubs Ltd | Hospitality | 2026 |
| Thebhoysengineering Ltd | Professional & scientific | 2022 |
| Theheart Ltd | Wholesale & retail | 2022 |
| Thehoptimistdraycott Ltd | Hospitality | 2024 |
| Thek Digital Limited | Professional & scientific | 2022 |
| Thelittle-Kitchen Ltd | Hospitality | 2019 |
| Thelittlecleaningcompany Ltd | Administrative & support | 2023 |
| Thelo Digital Ltd | Information & communication | 2026 |
| Themars Limited | Information & communication | 2026 |
| Themettle Limited | Extraterritorial | 2018 |
| Thenga Ltd | Wholesale & retail | 2025 |
| Thenomadfamily Ltd | Other services | 2025 |
| Thenutritionproject Limited | Health & social care | 2021 |
| Theo James Limited | Wholesale & retail | 2020 |
| Theobalddriver 01 Limited | Transport & logistics | 2015 |
| Theoneness Shop Ltd | Wholesale & retail | 2024 |
| Theonetouch Solutions Ltd | Information & communication | 2025 |
| Theplayerlink Ltd | Arts & recreation | 2024 |
| Thepossible Limited | Professional & scientific | 2026 |
| Thepropertylabs Ltd | Real estate | 2022 |
| Therapy 101 Ltd | Health & social care | 2020 |
| Therapy RN Ltd | Health & social care | 2023 |
| Therifleman Ltd | Hospitality | 2024 |
| Thermalmate (UK) Holdings Limited | Financial services | 2020 |
| Thermee Limited | Professional & scientific | 2026 |
| Thermofluid Tech Ltd | Professional & scientific | 2025 |
| Thesa Tech Consulting Limited | Information & communication | 2018 |
| Thesolidgroup Ltd | Education | 2025 |
| Thewellbeingbody Limited | Wholesale & retail | 2024 |
| THF Group Limited | Financial services | 2023 |
| THH Lean Ltd | Professional & scientific | 2018 |
| Thimblemill Properties Ltd | Real estate | 2025 |
| Thingoe Hill Management Company Ltd | Real estate | 2005 |
| Think Artist CIC | Education | 2025 |
| Think Code Release Ltd | Information & communication | 2012 |
| Think Film Ltd | Information & communication | 2019 |
| Think Ocean CIC | Manufacturing | 2021 |
| THINK3 Agency Limited | Professional & scientific | 2019 |
| THINK3 Studio Limited | Information & communication | 2019 |
| Thinkpol Training Ltd | Professional & scientific | 2012 |
| Thinkvation Limited | Administrative & support | 2024 |
| Thinwolf Entertainment Ltd | Information & communication | 2026 |
| Third MAN Theatre Ltd | Arts & recreation | 2012 |
| This IS Ibiza Ltd | Administrative & support | 2023 |
| This IS Scada Ltd | Information & communication | 2019 |
| Thiyaash Navya UK Ltd | Wholesale & retail | 2026 |
| THJ Property Investment Ltd | Real estate | 2023 |
| Thomas Haimes & Company Limited | Manufacturing | 1992 |
| Thomas Lloyd Estates Ltd | Real estate | 2024 |
| Thomas Matthew Bespoke Limited | Manufacturing | 2024 |
| Thomas Scudder Limited | Professional & scientific | 2004 |
| Thompson CM Limited | Financial services | 2018 |
| Thompson Dental Limited | Health & social care | 2024 |
| Thompson Residential Limited | Real estate | 2021 |
| Thomson & Thomson Enterprises Ltd | Agriculture & fishing | 2022 |
| Thomson UK Properties Limited | Real estate | 2026 |
| Thoresby Court Management Company Limited | Real estate | 1996 |
| Thorley Glade Residents Management Company Limited | Households | 2025 |
| Thorley Investments Limited | Financial services | 2025 |
| Thorley Support Services (TSS) Ltd | Health & social care | 2025 |
| Thornley Place (Ashbourne) Management Company Limited | Households | 2003 |
| Thorpe Property Ltd | Real estate | 2025 |
| Thorpeys Ltd | Professional & scientific | 2019 |
| THP1 Limited | Real estate | 2017 |
| Thread of Life Limited | Education | 2024 |
| Threads Alterations Company Ltd | Other services | 2018 |
| Three Brothers INT Ltd | Wholesale & retail | 2026 |
| Three Eight Consultancy Limited | Administrative & support | 2003 |
| Three Gables Nurseries Limited | Education | 2010 |
| Three MEN One Shed Ltd | Information & communication | 2002 |
| Three One Zero Design Ltd | Information & communication | 2015 |
| Threeblue Window Cleaning Ltd | Administrative & support | 2013 |
| Threeguru Ltd | Information & communication | 2013 |
| Threesixty Commercial Finance Limited | Professional & scientific | 2011 |
| Threesixty Innovation Limited | Wholesale & retail | 2000 |
| Thricemade Ltd | Information & communication | 2025 |
| Thrive Advice Ltd | Financial services | 2023 |
| Thrive Beyond Trauma CIC | Education | 2026 |
| Thrive Community Network CIC | Education | 2025 |
| Thrive Path Solutions Ltd | Health & social care | 2025 |
| Thriveconnect Ltd | Information & communication | 2025 |
| Thrivemind Village C.I.C. | Wholesale & retail | 2023 |
| Throne Beauty House Ltd | Other services | 2026 |
| Throttle Supply Ltd | Wholesale & retail | 2026 |
| Throughomes Ltd | Health & social care | 2020 |
| THS+ Ltd | Professional & scientific | 2020 |
| Thulston Associates Limited | Professional & scientific | 2017 |
| Thumbripper Investments Ltd | Real estate | 2018 |
| Thunderbird Property Inspections Limited | Real estate | 2026 |
| Thunderstruck Properties Ltd | Real estate | 2025 |
| Thurman Hambleton Enterprises Limited | Construction | 2014 |
| THW Holdings Ltd | Financial services | 2017 |
| Thyme Close Fotheringham 1964 Limited | Extraterritorial | 2014 |
| TI Live Ltd | Information & communication | 2020 |
| Tiar Limited | Professional & scientific | 2018 |
| Ticknall Solar Ltd | Manufacturing | 2011 |
| Tidal Shift Limited | Professional & scientific | 2026 |
| Tiddlywinks @ Ben’S Ltd | Wholesale & retail | 2020 |