| Three Bridges Australian Cobberdogs Limited | Harrow | 2026 |
| Three Chimneys Farm UK Ltd | Northamptonshire | 2026 |
| Three Counties Farms Limited | Marlborough | 2004 |
| Three Counties Honey Ltd | Milton Keynes | 2022 |
| Three Counties Hoof Care Ltd | Bewdley | 2022 |
| Three Counties Hunt Limited | Henley In Arden | 2004 |
| Three Counties International Transport Ltd | Bridport | 2010 |
| Three Fields Ltd | Petersfield | 2024 |
| Three Fishes Farms (Spraying & Livestock) Limited | Peterborough | 2013 |
| Three Fishes Farms Limited | Peterborough | 2009 |
| Three Generations Farming Limited | Gillingham | 2025 |
| Three Glovers Ltd | Aberystwyth | 2024 |
| Three Hares Organics CIC | Bristol | 2023 |
| Three Houses Equestrian Ltd | Codicote | 2025 |
| Three Jays Shellfish Limited | Newton Abbot | 2019 |
| Three Lakes Wormery Limited | Benfleet | 2018 |
| Three Musketeers Limited | Woodbridge | 2001 |
| Three Oaks Poultry Ltd | Tiverton | 2025 |
| Three Pastures Contracting Limited | Bungay | 2012 |
| Three Prospects Farm Limited | Margaret Roding | 1996 |
| Three Rivers Holdings Limited | Ipswich | 2015 |
| Three Shires Agronomy Limited | Northampton | 2004 |
| Three Shires Farm Limited | St. Albans | 2015 |
| Three Sisters Shropshire Limited | Beckenham | 2010 |
| Three Spires Honey Limited | Lichfield | 2026 |
| Three Spires Tree Care Limited | Knowle, Solihull | 2020 |
| Three Willows Lake Ltd | Dereham | 2019 |
| Three-Sixty Aquaculture Limited | Swansea | 2014 |
| Threepaddocks Ltd | Birmingham | 2025 |
| Thrift END Kennels & Pets Ltd | Flitton | 2018 |
| Thrift Farm Holdings Limited | Colchester | 2019 |
| Thrift Farm Limited | Essex | 1957 |
| Thrimby Farms Limited | Penrith | 2019 |
| Thrimley Stud Ltd | Ware | 2018 |
| Thriplow Farms Limited | Herts | 1939 |
| Thrive Aqua Group Ltd | St. Neots | 2025 |
| Thrive at Hideaway Wood Farm CIC | Northampton | 2024 |
| Thrive Equine Ltd | Arundel | 2026 |
| Thrive Oasis Ltd | London | 2026 |
| Thrive Poultry CIC | Plymouth | 2026 |
| Thriveunique Limited | Somerton | 1992 |
| Through the Loop Consulting Limited | Wokingham | 1996 |
| Throwley Poultry Ltd. | Faversham | 1997 |
| Thrupp Farms Limited | Daventry | 1997 |
| THS Sales Ltd | Colchester | 2024 |
| Thuborough Farms Ltd | Holsworthy | 2015 |
| Thulbourne Agricultural Contractor Limited | Swaffham | 2015 |
| Thundridge Community Orchard Trust Limited | Ware | 2017 |
| Thurloe Breeding Ltd | Carryduff | 2025 |
| Thurlow Estate Farms Limited | Haverhill | 2009 |
| Thurso Limited | Newmarket | 2005 |
| Thurso River Limited | Forfar | 2005 |
| Thuscombe Ltd | Spalding | 2017 |
| TI Conservation Ltd | Burnley | 2016 |
| Tiamat Agriculture Ltd | Weybridge | 2019 |
| Tianxi Metal Co., Ltd | Cambridge | 2023 |
| Tibbs Tree Surgeons Ltd | Wells | 2013 |
| Tiberius Blue Ltd | Newton Abbot | 2020 |
| Tibor Darvas Limited | Kingswood | 1962 |
| TIC Poultry Limited | Omagh | 2011 |
| Tickage Ltd | Cirencester | 2016 |
| Tickenham Court Farm Co.Limited | Clevedon | 1946 |
| Tickhill Kennels Ltd | Doncaster | 2016 |
| Tictac Horses & Ponies Ltd | Oakham | 2023 |
| Tidal Hill Limited | Woodbridge | 2009 |
| Tidal Paws Limited | Barnsley | 2017 |
| Tidbury Stone Limited | Coventry | 2017 |
| Tidcombe Farming Limited | Marlborough | 2011 |
| Tidcombe FEN Society Limited | Tiverton | 2001 |
| Tideline Investments Ltd | Dundee | 2021 |
| Tideline Solutions Ltd | King'S Lynn | 2023 |
| Tiderock Ltd | Holsworthy | 2017 |
| Tidewood Limited | Crowborough | 2023 |
| Tidy Dog - Dog Grooming & Spa Ltd | Aberteifi | 2021 |
| Tidywork UK Limited | Reading | 2018 |
| Tierney Farm Ltd | Glasgow | 2026 |
| Tierson Farms Limited | Carmarthen | 2002 |
| Tifan Ltd | Gillingham | 2020 |
| Tiffey Valley Ltd | Norwich | 2017 |
| Tight Lines Community Interest Company | Truro | 2022 |
| Tigitt Limited | Aberdeenshire | 2003 |
| TII Aquaculture Limited | St. Austell | 2019 |
| Tijite Ltd | Wolverhampton | 2024 |
| Tijou Contracting Services Ltd | Strichen | 2017 |
| Tiki's Teepee Ltd | Leeds | 2022 |
| Tikus Limited | Loughborough | 1999 |
| Tikvah Doodles Ltd | Malpas | 2014 |
| TIL Forestry Ltd | Forres | 2014 |
| Tila Farming Limited | Leicester | 2025 |
| Tile Kiln Farm Limited | Halstead | 2023 |
| Tile Place Equine Limited | Hemel Hempstead | 2026 |
| Tilery Equestrian Centre Limited | Wallsend | 2006 |
| Tilhill Forestry Limited | Altrincham | 1996 |
| Tilia (Foulsham) Limited | Norwich | 2008 |
| Tilia Market Garden Ltd | Hempnall | 2022 |
| Tilia Tree Care Ltd | Whitchurch | 2025 |
| Tilia Tree Consultancy Services Ltd | Morpeth | 2022 |
| Till & Toil Equipment Ltd | Cardiff | 2025 |
| Till Valley Contracting Limited | Salisbury | 2008 |
| Tillers Turf Company Limited | Grantham | 1989 |