| Therapaedic Limited | Health & social care | 2022 |
| Therapy Integrate Limited | Other services | 2022 |
| Theresa Care Management Limited | Other services | 2013 |
| Thermal Security Systems Ltd | Administrative & support | 2022 |
| Thermal Spray Services Limited | Manufacturing | 2008 |
| Thessaly Court Management Company Limited | Households | 2002 |
| Theszn Ltd | Wholesale & retail | 2024 |
| Theta Engineering Ltd | Professional & scientific | 2023 |
| Thevioletcollective Ltd | Arts & recreation | 2026 |
| They DO Dough Ltd | Hospitality | 2019 |
| THG Automotive Limited | Wholesale & retail | 2026 |
| Thie Holdings Limited | Other services | 2021 |
| Thighs of Steel C.I.C. | Other services | 2017 |
| Thimble Construction Limited | Construction | 2022 |
| Thin Reel Media Limited | Information & communication | 2017 |
| Think BIM Limited | Professional & scientific | 2020 |
| Think Performance Limited | Professional & scientific | 2016 |
| Think PMO Limited | Administrative & support | 2015 |
| Thinking Juice Holdings Limited | Financial services | 2016 |
| Thinking Juice Limited | Professional & scientific | 2005 |
| Third Side Limited | Wholesale & retail | 2012 |
| Third Version Creative Limited | Arts & recreation | 2023 |
| Thirst First Water Coolers Limited | Wholesale & retail | 2009 |
| Thirsty Willow Bar Company Ltd | Hospitality | 2025 |
| Thirty 12 Events Ltd | Other services | 2017 |
| This Group Limited | Real estate | 2016 |
| This IS Focus Ltd | Information & communication | 2011 |
| This IS Gain Bidco Limited | Financial services | 2021 |
| This IS Gain Global Limited | Financial services | 2018 |
| This IS Gain Ltd | Professional & scientific | 2024 |
| This IS Gain Midco Limited | Financial services | 2021 |
| This IS Gain Topco Limited | Financial services | 2021 |
| This IS Paria Ltd | Wholesale & retail | 2025 |
| Thistle Parking Limited | Extraterritorial | 1998 |
| Thom & Son's Ltd | Health & social care | 2024 |
| Thomas Search Limited | Administrative & support | 2013 |
| Thompson Digital Ltd | Wholesale & retail | 2022 |
| Thomson Rigging Ltd | Manufacturing | 2017 |
| Thornbury Management (Westbourne) Limited | Households | 1973 |
| Thornham Marina Limited | Administrative & support | 2002 |
| Thornhill Consulting Ltd | Professional & scientific | 2008 |
| Thorpe Engineering Consultants Limited | Professional & scientific | 2012 |
| Thosai Limited | Hospitality | 2018 |
| Those That Dare Ltd | Professional & scientific | 2021 |
| Thread & Pipe Services Limited | Manufacturing | 1975 |
| Threader Technologies Limited | Information & communication | 2026 |
| Three and One Limited | Real estate | 2023 |
| Three County Scaffolding Limited | Construction | 2024 |
| Three Oaks (Newport) MAN Co Ltd | Households | 2024 |
| Threeways Limited | Wholesale & retail | 2004 |
| Thrinakia Partnership Ltd | Financial services | 2025 |
| Thrive Well Elaglobal Service Ltd | Public administration | 2024 |
| THS Financial Management Ltd | Professional & scientific | 2024 |
| Thyme Accounting Services Limited | Professional & scientific | 2014 |
| Thyme Business Services Limited | Administrative & support | 2021 |
| Tibbshealthcare Limited | Wholesale & retail | 2019 |
| TIC TAC Ltd | Professional & scientific | 2026 |
| Tick Talent Ltd | Administrative & support | 2023 |
| Tidal Power Services Ltd | Construction | 2014 |
| Tidalwood Limited | Manufacturing | 2025 |
| Tide Pilates Limited | Health & social care | 2025 |
| Tide Plumbing & Heating Ltd | Construction | 2016 |
| Tides Flat Management Limited | Administrative & support | 2014 |
| Tideways Property Ltd | Real estate | 2020 |
| Tidy & Spotless Cleaners Limited | Administrative & support | 2024 |
| Tidy Touch Cleaners Ltd | Administrative & support | 2025 |
| Tier 1 Martial Arts Limited | Professional & scientific | 2020 |
| Tier 1 Protection (International) Limited | Administrative & support | 2025 |
| Tiger Bengal Ltd | Hospitality | 2025 |
| Tiger Investment Company Limited | Households | 2005 |
| Tijara London Limited | Professional & scientific | 2013 |
| Tika Ltd | Professional & scientific | 2025 |
| Tile Projects Ltd | Wholesale & retail | 2023 |
| Tilikum Wealth Management Limited | Financial services | 2017 |
| Till Late Ltd | Wholesale & retail | 2026 |
| Till Roll King Limited | Wholesale & retail | 2010 |
| Tilted WIG Productions Ltd | Arts & recreation | 2017 |
| TIM Africa AID (UK) Ltd | Health & social care | 2025 |
| Timbacut Ltd. | Construction | 2006 |
| Timber Craft Carpentry Ltd | Construction | 2023 |
| Timber Transformations Ltd | Construction | 2023 |
| Time Mortgage Experts Ltd | Financial services | 2012 |
| Timms Agencies Limited | Real estate | 2016 |
| Timpani Films Limited | Information & communication | 2010 |
| TIN ATA Kazna Publishing Limited | Information & communication | 2015 |
| Tingalink Ltd | Hospitality | 2025 |
| Tiny Seeds Preschool Ltd | Education | 2026 |
| Tipadel Limited | Wholesale & retail | 1987 |
| Tipply Ltd | Information & communication | 2015 |
| Tips Away Ltd | Water & waste | 2020 |
| Tirumala Services Limited | Administrative & support | 2009 |
| Tisbury Community Homes Ltd | Construction | 2019 |
| Titania Surgical Ltd. | Health & social care | 2017 |
| Titanic Tattoo and Piercing Ltd | Other services | 2021 |
| Titb Itchenor Ltd | Real estate | 2025 |
| Titb Limited | Real estate | 2024 |
| Tithe Property Ltd | Construction | 2025 |
| Titus Graphics Limited | Professional & scientific | 1999 |
| Tiverton Court (Bournemouth) Management Company Limited | Households | 2025 |
| Tivoli Court (Bournemouth) Management Company Limited | Households | 1976 |