| This Other Eden Ltd | Wholesale & retail | 2023 |
| Thistle Floristry Ltd | Wholesale & retail | 2026 |
| THL Terminal Ltd | Transport & logistics | 1998 |
| Thomas Bell Consulting Ltd | Professional & scientific | 2023 |
| Thomas Bidco Limited | Financial services | 2013 |
| Thomas Elliot Investments Limited | Real estate | 2021 |
| Thomas Hewitt Ltd | Information & communication | 2013 |
| Thomas James Solutions Group Limited | Administrative & support | 2024 |
| Thomas James Wealth Management Limited | Financial services | 2025 |
| Thomas Jones Estates (Yorks) Ltd | Real estate | 2022 |
| Thomas Knights Ltd | Manufacturing | 2015 |
| Thomas Midco Limited | Financial services | 2013 |
| Thomas of York Limited | Manufacturing | 1963 |
| Thomas Peacock Ltd | Construction | 2022 |
| Thomas Pilcher Homes Limited | Construction | 2013 |
| Thomas Taylor Limited | Hospitality | 2026 |
| Thomas Topco Limited | Financial services | 2013 |
| Thomas Wilson & Co (Cabinetry) Limited | Manufacturing | 2023 |
| Thomlinson Services (York) Limited | Construction | 2008 |
| Thompson and Moore Ltd | Construction | 2025 |
| Thompson Commercial Vehicles Hire and Sales Limited | Wholesale & retail | 2025 |
| Thompson Global Logistics Limited | Other services | 2009 |
| Thompson Lets Ltd | Real estate | 2019 |
| Thompson M&E Services Ltd | Other services | 2026 |
| Thompson Properties N.Y. Ltd | Real estate | 2015 |
| Thompson Properties York Ltd | Construction | 2023 |
| Thompsons Accountants Limited | Professional & scientific | 2005 |
| Thompsons Asbestos Services Ltd | Water & waste | 2021 |
| Thompsons of Prudhoe Holding Ltd. | Administrative & support | 1957 |
| Thompsons of Prudhoe Limited | Construction | 1974 |
| Thompsons Roofing Services Limited | Construction | 2015 |
| Thompsons Timberworks Limited | Construction | 2018 |
| Thompson’S Traditional Fish and Chips Limited | Hospitality | 2022 |
| Thonock Green (Gainsborough) Management Company Limited | Real estate | 2024 |
| Thor Switchgear Ltd | Manufacturing | 2024 |
| Thor's Events Ltd | Hospitality | 2021 |
| Thora Limited | Wholesale & retail | 2017 |
| Thorialine Ltd | Real estate | 2022 |
| Thorne Engineers Ltd. | Manufacturing | 2012 |
| Thornhall LLP | | 2025 |
| Thornhill (Boston Spa) Management Company Limited | Households | 1987 |
| Thornley Woods (Gateshead) Management Company Limited | Households | 2016 |
| Thornmere Millpool Limited | Professional & scientific | 2023 |
| Thornton Abbott Holdings Ltd | Professional & scientific | 2018 |
| Thornton Abbott Investments Limited | Professional & scientific | 2015 |
| Thornton Associates (Yorkshire) Ltd | Administrative & support | 2007 |
| Thornton Lodge Country Sports Ltd | Arts & recreation | 2004 |
| Thornton Real Estates Ltd | Real estate | 2025 |
| Thornton's Bakehouse & Butchers Limited | Wholesale & retail | 2021 |
| Thorpe Dental Education Centre Limited | Education | 2023 |
| Thorpe Dental Group Limited | Health & social care | 2006 |
| Thorpe Dental Implant Centre LLP | | 2018 |
| Thorpe Harcaster Limited | Professional & scientific | 2024 |
| Thorpe Trees Limited | Wholesale & retail | 2004 |
| Thorpe Underwood Limited | Extraterritorial | 2015 |
| Thors Ghyll Ltd | Real estate | 2023 |
| Thorstar Limited | Real estate | 2017 |
| Thought Associates Ltd | Information & communication | 2021 |
| Thought-Full Box Ltd | Wholesale & retail | 2018 |
| Thoughtsun Limited | Information & communication | 2014 |
| Thousand Drums Ltd | Information & communication | 2016 |
| Thread and Press CIC | Arts & recreation | 2020 |
| Three 60 Marketing (Yorkshire) Limited | Professional & scientific | 2004 |
| Three Brothers Developments Limited | Real estate | 2015 |
| Three Cranes 21 Ltd | Real estate | 2021 |
| Three Eagles Capital Limited | Financial services | 2011 |
| Three Eagles Group (UK) Limited | Financial services | 2011 |
| Three Graces Galleries Limited | Extraterritorial | 2018 |
| Three Guys Spice Ltd | Hospitality | 2020 |
| Three Little Birds (York) LLP | | 2014 |
| Three Sisters Media (UK) Limited | Administrative & support | 2017 |
| Three SIX Echo Limited | Construction | 2011 |
| Three Sixty Fmcg Ltd | Professional & scientific | 2024 |
| Three Thousand Productions Ltd | Information & communication | 2024 |
| Threepwood Heating Limited | Energy | 2014 |
| Thrive Outside CIC | Other services | 2020 |
| Thrive Well Strategies Ltd | Health & social care | 2026 |
| THS Productions Limited | Information & communication | 2015 |
| THS Property Limited | Real estate | 2025 |
| Thula Pilates & Wellness Ltd | Arts & recreation | 2026 |
| Thumbmunkeys Ltd | Information & communication | 2014 |
| Thundering Computing Ltd | Information & communication | 1998 |
| Thunk-It Theatre CIC | Arts & recreation | 2021 |
| Thysis Technical Mouldings Ltd | Manufacturing | 2013 |
| Ti'Africa Ltd | Wholesale & retail | 2023 |
| Tickertape Labs Limited | Information & communication | 2014 |
| Tickety BOO Property Limited | Real estate | 2021 |
| Tiddler Inc Limited | Wholesale & retail | 2022 |
| Tiddler Investments Ltd | Real estate | 2015 |
| Tiddlywinks Boroughbridge Limited | Administrative & support | 2024 |
| Tiddlywinks Easingwold Limited | Education | 1999 |
| Tiddlywinks Private Day Nurseries Limited | Education | 2003 |
| TIE IT UP Theatre (North) Ltd | Education | 2023 |
| Tiger Drop Games Ltd | Information & communication | 2024 |
| Tiggle Ventures Ltd | Manufacturing | 2026 |
| Tigmon Solitons Ltd | Professional & scientific | 2020 |
| Tile With Style (York) Limited | Wholesale & retail | 2003 |
| Tilia Fields Ltd | Financial services | 2024 |
| Tillett Consulting Engineers Ltd | Professional & scientific | 2014 |
| Tilly Journals Ltd | Manufacturing | 2019 |