| Torrent Drainage Services Limited | Water & waste | 2021 |
| Tory Barne Ltd | Professional & scientific | 2025 |
| Total BIO Solutions Limited | Construction | 2011 |
| Total Damp Surveys Limited | Construction | 2023 |
| Total Transformation Aesthetics Ltd | Other services | 2022 |
| Townsend Bearing and Transmission Limited | Wholesale & retail | 1985 |
| Townsend Enterprises Ltd | Wholesale & retail | 2023 |
| Townsend SEO Limited | Information & communication | 2022 |
| TP Disposals Ltd | Water & waste | 2021 |
| TPB Precision Engineering Ltd | Manufacturing | 2018 |
| Tracey Structures Limited | Construction | 2003 |
| Traction Sports Surfaces Ltd | Professional & scientific | 2023 |
| Tractor Operations & Parts Limited | Manufacturing | 2019 |
| Trailblazers Property Limited | Real estate | 2020 |
| Training Advisor Limited | Professional & scientific | 2016 |
| Training Services (UK) Limited | Professional & scientific | 1992 |
| Transec Electric Limited | Administrative & support | 2018 |
| Transition Town Dorchester CIC | Agriculture & fishing | 2014 |
| Travel for Media Ltd | Information & communication | 2015 |
| Treehope Travel Limited | Administrative & support | 2024 |
| Treehouse Developments (Dorset) Limited | Construction | 2003 |
| Treetops Allbrook Management Company Limited | Households | 2019 |
| Treowuk Limited | Professional & scientific | 2023 |
| Trickjump Games Limited | Information & communication | 2017 |
| Trinity Street Development Ltd | Real estate | 2025 |
| Trinitycorp Ltd | Hospitality | 2019 |
| Triple Edge Solutions Limited | Administrative & support | 2020 |
| Triple R Restoration Limited | Wholesale & retail | 2015 |
| Tritex NDT Limited | Manufacturing | 2006 |
| Trudy DE Groot Limited | Professional & scientific | 2021 |
| TSR Aviation Ltd | Manufacturing | 2022 |
| TT Koshy Ltd | Health & social care | 2014 |
| TTS Media and Communications Ltd | Construction | 2019 |
| TTT Carpentry Limited | Construction | 2014 |
| Tudor Cafe (Hoddesdon) Limited | Real estate | 1935 |
| Turner Equestrian Services Limited | Agriculture & fishing | 2018 |
| Turnwall Developments Limited | Real estate | 2016 |
| Twenty SIX Belsize Park Limited | Hospitality | 1987 |
| Twenty Two Property Holdings Ltd | Real estate | 2021 |
| Twine Limited | Information & communication | 2014 |
| Two Harbour View RTM Co. Ltd. | Households | 2011 |
| Two Roads Capital Limited | Real estate | 2025 |
| TWO57 Motors Ltd | Wholesale & retail | 2026 |
| TWR Lighting & Electrical Limited | Construction | 2014 |
| Tyberton Court Management Company Limited | Households | 2009 |
| Tyre Wholesale Direct Ltd | Wholesale & retail | 2024 |
| Tyres of Dorset Ltd | Wholesale & retail | 2024 |
| Tytherleigh-West Ltd | Professional & scientific | 2022 |
| U-Reka Club Ltd | Wholesale & retail | 2018 |
| Ucam Solutions Ltd | Construction | 2022 |
| UK Catering Hire Limited | Administrative & support | 2022 |
| UK Green Energy TEC Limited | Other services | 2016 |
| UK Pride Electrical Ltd | Construction | 2023 |
| UK Yacht Surveyors Ltd | Professional & scientific | 2013 |
| Ukhi Limited | Wholesale & retail | 2020 |
| ULA Pontikos Ltd | Information & communication | 2012 |
| Ultimate Fitness Dorset Ltd | Arts & recreation | 2015 |
| Unbottle Ltd | Financial services | 2022 |
| Uncoverai Ltd | Professional & scientific | 2023 |
| Under the Greenwood Tree Cafe Ltd | Hospitality | 2015 |
| Underdogs Wellbeing Community Interest Company | Health & social care | 2024 |
| Underfloorheating Solutions UK Limited | Construction | 2016 |
| Unique Installations Limited | Construction | 2003 |
| Universal Executive Properties Ltd | Real estate | 2018 |
| Universal Pet Supplies Limited | Wholesale & retail | 2023 |
| Universal Suppliers and Expeditors Limited | Professional & scientific | 2022 |
| Unloup Limited | Professional & scientific | 2000 |
| Unltd Group Limited | Extraterritorial | 2025 |
| Untitled London Limited | Administrative & support | 2013 |
| UP Kitchens Ltd | Construction | 2020 |
| UP Sydling Biomass Ltd | Energy | 2013 |
| Upper Linhay Associates Limited | Real estate | 1986 |
| Upshall Business Partners LLP | | 2018 |
| Urban Wild Education CIC | Education | 2016 |
| Utilities & Merchant Services Ltd | Other services | 2024 |
| Vahsel Consultancy Limited | Professional & scientific | 2020 |
| Valve Space Ltd | Information & communication | 2018 |
| Vantage Way (Poole) Management Company NO. 2 Limited | Professional & scientific | 2004 |
| Vaperstar Limited | Wholesale & retail | 2016 |
| Vaspba Remote Piloted Systems Limited | Wholesale & retail | 2018 |
| Vatax Accounting Limited | Professional & scientific | 2013 |
| VBS Properties Ltd | Real estate | 2023 |
| Veale & Co Limited | Professional & scientific | 2012 |
| Veianna Creations Ltd | Hospitality | 2024 |
| Velocity Sales Consulting Ltd | Professional & scientific | 2026 |
| Venabuild Ltd | Manufacturing | 2021 |
| Venchards Limited | Hospitality | 2019 |
| Venture Management Holdings Ltd | Professional & scientific | 2017 |
| Venture Rose Letting Ltd | Real estate | 2021 |
| Vertrek Consulting Limited | Administrative & support | 2014 |
| Verwood Surplus Stores Limited | Wholesale & retail | 2013 |
| Vespauk Limited | Construction | 2023 |
| Vickery Holdings Limited | Financial services | 2021 |
| Vickery Tate Limited | Agriculture & fishing | 2024 |
| Victor Baldwin (High Wycombe) Limited | Real estate | 1986 |
| Victor Jackson Avenue (Poundbury) Management Company Limited | Households | 2002 |
| Victoria Court Management Company (Weymouth) Limited | Real estate | 2001 |
| Victoria Court Management Company Limited | Households | 1988 |
| Victoria Macpherson Limited | Administrative & support | 2013 |
| Victory Court Flats Limited | Households | 1973 |