| Terminator Pest Control & Environmental Services Limited | Extraterritorial | 2016 |
| Terminator Pest Control Limited | Health & social care | 2000 |
| Terry's Sports Auctions Ltd | Wholesale & retail | 2022 |
| Tester Racing and Engineering Ltd | Wholesale & retail | 2018 |
| Tester Racing Engines Limited | Manufacturing | 2008 |
| TG Home Improvements Limited | Construction | 2022 |
| TGK Pubs Ltd | Hospitality | 2026 |
| TH Spa Farm Limited | Construction | 2022 |
| TH ST Ipps Limited | Construction | 2024 |
| TH Towcester Grange Limited | Construction | 2022 |
| Thames Valley Aggregates Limited | Administrative & support | 2009 |
| THE A.R.C. Freehold Limited | Households | 1997 |
| THE Appropriate Adult Service Limited | Public administration | 2007 |
| THE Bays Ltd | Other services | 2024 |
| THE British Society of Dental Hygiene and Therapy Limited | Other services | 2001 |
| THE Cottesmore Business Park Management Company Limited | Real estate | 2004 |
| THE Courage to Choose Ltd | Education | 2023 |
| THE Creative Block Limited | Real estate | 2022 |
| THE Dangerous Goods Consultant Ltd | Professional & scientific | 2021 |
| THE Darts Hole Limited | Wholesale & retail | 2025 |
| THE Daventry Club Limited | Hospitality | 2025 |
| THE Daventry Masonic Club Company, Limited | Real estate | 1965 |
| THE Escape Game - Party Box Ltd | Arts & recreation | 2024 |
| THE Eydon Kettle Company Limited | Manufacturing | 1996 |
| THE Farming Community Network | Information & communication | 2002 |
| THE Financial Wellbeing Hub Ltd | Education | 2023 |
| THE Garden Room Construction Ltd | Construction | 2017 |
| THE Golf Zone Ltd | Wholesale & retail | 2011 |
| THE Grocutt Workshop Ltd | Construction | 2026 |
| THE Hinton Project Limited | Wholesale & retail | 2014 |
| THE Hovel at Hinton Ltd | Arts & recreation | 2012 |
| THE HR Consultancy Group Limited | Professional & scientific | 2024 |
| THE Hungry Trailer Ltd | Hospitality | 2025 |
| THE Joint Competence Initiative Limited | Other services | 2025 |
| THE LAB Agency Limited | Other services | 2022 |
| THE Little Cotswold Company Ltd | Extraterritorial | 2023 |
| THE Lyft Collective Ltd | Wholesale & retail | 2024 |
| THE N Bar Ltd | Hospitality | 2026 |
| THE Neale Agency Limited | Administrative & support | 2011 |
| THE Oak Eydon Limited | Hospitality | 2024 |
| THE Olive Tree Workshop Ltd | Other services | 2025 |
| THE Omega Group (Europe) Limited | Professional & scientific | 2024 |
| THE Omega Group (Operations) Limited | Professional & scientific | 2016 |
| THE Omega Group (R&D) Limited | Professional & scientific | 2025 |
| THE Padel Consultants Ltd | Professional & scientific | 2025 |
| THE Pharmacy Consultancy Limited | Financial services | 2010 |
| THE Plough Inn Everdon Limited | Hospitality | 2022 |
| THE Poplars (2025) Ltd | Agriculture & fishing | 2025 |
| THE Psychology OWL Limited | Health & social care | 2025 |
| THE R Oak Eydon Ltd | Hospitality | 2022 |
| THE Rarely Seen Slug Ltd | Transport & logistics | 2020 |
| THE Reach for Health Centre Ltd | Health & social care | 2010 |
| THE Red Lion at Hunningham Ltd | Hospitality | 2016 |
| THE Rover P6 Club Ltd | Other services | 2024 |
| THE Salon at Twenty Four Ltd | Other services | 2025 |
| THE Sausage Project Ltd | Hospitality | 2022 |
| THE Sense of Hearing Limited | Wholesale & retail | 2021 |
| THE Shires Catering Limited | Hospitality | 2022 |
| THE Silver Goose Ltd | Wholesale & retail | 2021 |
| THE Society of Leather Technologists and Chemists Limited | Other services | 1951 |
| THE Sound Tailor Limited | Wholesale & retail | 2024 |
| THE Sport Trap Company Limited | Arts & recreation | 2022 |
| THE Storybook Play Cafe Ltd | Hospitality | 2025 |
| THE Urban Dairy Limited | Manufacturing | 2025 |
| THE Warwick Co Ltd. | Professional & scientific | 2020 |
| THE Wellnaissance Ltd | Health & social care | 2025 |
| THE XLC Print Studio Ltd | Administrative & support | 2024 |
| THE Young Leaders Nexus Ltd | Information & communication | 2024 |
| Think on Engineering Limited | Manufacturing | 2018 |
| This IS Enough Limited | Professional & scientific | 2024 |
| Thomas Heritage and Country Ltd | Construction | 2010 |
| Thomas Partridge & Company Limited | Extraterritorial | 2010 |
| Thorgals Car Finish Ltd | Wholesale & retail | 2021 |
| Three Hens Limited | Financial services | 2012 |
| Three Minds Psychology Ltd | Health & social care | 2023 |
| Three Pillars Rehabilitation Limited | Health & social care | 2019 |
| Three Shires Trailers Limited | Wholesale & retail | 2020 |
| Thrupp Farms Limited | Agriculture & fishing | 1997 |
| Tigaca Limited | Professional & scientific | 2005 |
| Tigervpns Ltd | Professional & scientific | 2013 |
| Time House Services Limited | Administrative & support | 1994 |
| Timewarp Projects Ltd | Professional & scientific | 2014 |
| Timken Way 1963 Limited | Extraterritorial | 2014 |
| Timothy Howard Smith Ltd. | Construction | 2004 |
| TIN CAN Pizza Ltd. | Hospitality | 2025 |
| Titan Business Finance Limited | Financial services | 2025 |
| Titches Playroom Ltd | Hospitality | 2026 |
| TJ Bartlett Procurements Ltd | Administrative & support | 2019 |
| TLR Carcom Engineering Ltd | Manufacturing | 2021 |
| TLR Carcom Limited | Manufacturing | 2012 |
| Tltm Ltd | Professional & scientific | 2025 |
| TMS Building Contractors Ltd | Construction | 2022 |
| TN Enforcement Ltd | Administrative & support | 2019 |
| Tom's Driving Services Ltd | Transport & logistics | 2025 |
| Tomasz Podlaski Ltd | Manufacturing | 2026 |
| Tomi Trans Ltd | Transport & logistics | 2016 |
| Tommy Smith Heating and Plumbing Ltd | Construction | 2020 |
| Tonca Electronic Technology Co., Ltd | Manufacturing | 2020 |
| Toner Landscapes Ltd | Administrative & support | 2021 |
| Tonka's Plumbing and Heating Ltd | Construction | 2012 |