| THE Willows (Swallowfield) Management Company Limited | Households | 2017 |
| THE Window Specialist Limited | Construction | 2025 |
| THE Wood Monkey Limited | Manufacturing | 2009 |
| THE Woodlands (Barrow in Furness) Management Company Limited | Real estate | 2017 |
| THE Woodlands (Gateacre) Management Company Limited | Households | 2003 |
| THE Woodley Headland Management Company Limited | Households | 1991 |
| THE Woodstock Corporation Limited | Extraterritorial | 2007 |
| THE World Awaits YOU Travel Ltd | Administrative & support | 2019 |
| THE Wyld Bunch Ltd | Professional & scientific | 2020 |
| THE Xara Group Limited | Information & communication | 1995 |
| THE12THMAN Ltd | Construction | 2020 |
| THE4D Limited | Professional & scientific | 2023 |
| Theatre Academy High Wycombe Ltd | Education | 2014 |
| Thebrickhouse Company Ltd | Administrative & support | 2006 |
| Thebukachefbydee Ltd | Administrative & support | 2022 |
| Thechangeco Limited | Professional & scientific | 2015 |
| Theglobalexec Ltd | Professional & scientific | 2021 |
| Therainbow CIC | Education | 2022 |
| Therapy Zone Limited | Other services | 2011 |
| Theravada Monastic Trust | Other services | 2008 |
| Theresa Eaton Accounts Services Limited | Professional & scientific | 2013 |
| Thermoliv Limited | Construction | 2021 |
| Thesohoinn Ltd | Construction | 2025 |
| Theydon Mews Management Company Limited | Households | 2014 |
| Thinky Squid Ltd | Information & communication | 2017 |
| Third Party Solutions Limited | Administrative & support | 2016 |
| Thirdline Properties Ltd | Real estate | 2015 |
| Thirdline Studio Ltd | Real estate | 2021 |
| Thomas Noah Designs Limited | Professional & scientific | 2011 |
| Thornbury Gardens (Dinnington) Management Company Limited | Households | 2022 |
| Thorne Surveying Solutions Limited | Professional & scientific | 2011 |
| Thornyfields Management Company Limited | Households | 2004 |
| Three Piece Events Ltd | Hospitality | 2019 |
| Three Shires Leisure Ltd | Wholesale & retail | 2014 |
| Threeways (Northall) Ltd | Real estate | 2017 |
| Thrive Homes Finance PLC | Financial services | 2014 |
| Thrive Places Limited | Real estate | 2019 |
| Thugo Ltd | Information & communication | 2013 |
| Thukela Limited | Information & communication | 2013 |
| Thumper 69 Limited | Extraterritorial | 2015 |
| Thurso House (Dunston Riverside) Management NO 1 Limited | Households | 2003 |
| Thurso House (Dunston Riverside) Management NO 3 Ltd | Households | 2004 |
| Thurso House (Dunston Riverside) Management NO 4 Ltd | Households | 2004 |
| Tiana's Homes Ltd | Real estate | 2017 |
| Tickets House Limited | Administrative & support | 2016 |
| Tickle Communications Limited | Professional & scientific | 2022 |
| Tidny Healthcare Limited | Health & social care | 2025 |
| Tierney Rigging Services Limited | Construction | 2024 |
| Tierrasphere Limited | Professional & scientific | 2021 |
| Tiertech Ltd | Other services | 2019 |
| Tigarani Limited | Professional & scientific | 2011 |
| Tiger Clean Ltd | Administrative & support | 2020 |
| Tiger Line Ltd | Transport & logistics | 2025 |
| Tiger RAY Limited | Information & communication | 2015 |
| Tile Europe Ltd | Information & communication | 2016 |
| Tile Place Equine Limited | Agriculture & fishing | 2026 |
| Tileworks Ltd | Construction | 2017 |
| Tillers Close Management Company Limited | Households | 2010 |
| TIM Kyle Creative Limited | Professional & scientific | 2015 |
| Time (Apartments) Management Company Limited | Households | 2011 |
| Time for Change Ltd | Wholesale & retail | 2022 |
| Timephasing Ltd | Information & communication | 2022 |
| Timothy Property Development Limited | Construction | 2025 |
| Tina Childs Ltd | Other services | 2017 |
| Tinolard Care Ltd | Health & social care | 2023 |
| Tinolard UK Limited | Health & social care | 2015 |
| Tirangaevents Limited | Professional & scientific | 2023 |
| Tiroler Ltd | Hospitality | 2021 |
| Titus Solus Limited | Professional & scientific | 2014 |
| TJ Home Refurb Ltd | Construction | 2025 |
| Tjdb Limited | Manufacturing | 1994 |
| TJS Building Contractor Ltd | Construction | 2021 |
| TJW Management & Sourcing Ltd | Administrative & support | 2023 |
| TK Store Ltd | Wholesale & retail | 2024 |
| TK Tiling Solutions Ltd | Construction | 2023 |
| TLI NO 1 Limited | Households | 2004 |
| TLZ Realty Ltd | Real estate | 2019 |
| TM Accommodations Ltd | Real estate | 2025 |
| TM Property Assets Limited | Real estate | 2022 |
| TMF Hair & Beauty Limited | Wholesale & retail | 2012 |
| TN Residential Ltd | Real estate | 2025 |
| TNB Direct Ltd | Wholesale & retail | 2025 |
| TNR Solutions Ltd | Professional & scientific | 2024 |
| Toby Staines Limited | Administrative & support | 2025 |
| Tocs Laboratory Ltd | Health & social care | 2025 |
| Toggleclass Limited | Information & communication | 2016 |
| Toha Limited | Manufacturing | 2025 |
| Tolro Health Care Limited | Health & social care | 2022 |
| TOM Boother Limited | Administrative & support | 2013 |
| TOM Smith Fencing Limited | Construction | 2021 |
| Tomasz Stankiewicz Ltd | Wholesale & retail | 2024 |
| Tomi Facades Ltd | Public administration | 2025 |
| Tomlinson Financial Services Ltd | Financial services | 2019 |
| Tones the Studio Limited | Other services | 2026 |
| Tonyvone Limited | Health & social care | 2016 |
| Top Augustine Limited | Construction | 2025 |
| Top Cat Software Ltd | Information & communication | 2024 |
| Top Deck Business Services Ltd | Professional & scientific | 2000 |
| Top Drains & General Groundworks Ltd | Construction | 2020 |
| Top Education Consultants Ltd | Education | 2025 |