| Tent Maker Ltd | Transport & logistics | 2023 |
| Tentazioni (UK) Limited | Wholesale & retail | 2005 |
| TEO & DOR Ltd | Transport & logistics | 2017 |
| TEO Catalin Ltd | Professional & scientific | 2025 |
| TEO Cons Ltd | Construction | 2024 |
| TEO Exclusive Ltd | Wholesale & retail | 2022 |
| Teqniq Limited | Administrative & support | 2015 |
| Tequila and Lime Northampton Limited | Hospitality | 2024 |
| Tera Services Limited | Transport & logistics | 2024 |
| Terant Supplies Limited | Extraterritorial | 1981 |
| Terence Property Limited | Real estate | 2025 |
| Teri Pengilley Photography Ltd | Professional & scientific | 2018 |
| Termination NO. 9 Limited | | 1948 |
| Terra Logistics Ltd | Wholesale & retail | 2018 |
| Terra Mari Ltd | Real estate | 2017 |
| Terra Mater Ltd | Public administration | 2026 |
| Terraflo Systems Limited | Information & communication | 2000 |
| Tesc Ltd | Wholesale & retail | 2025 |
| Tesit Ltd | Information & communication | 2011 |
| Tessera Group Limited | Professional & scientific | 2024 |
| Test Systems Engineering Ltd | Professional & scientific | 2024 |
| Tester Roofing Limited | Construction | 2025 |
| Testimony Properties Ltd | Real estate | 2025 |
| Testuk Ltd | Professional & scientific | 2019 |
| Tetrix Solutions Limited | Information & communication | 2000 |
| Textbook Carpets Limited | Administrative & support | 1997 |
| Textile Trades Publishing Limited | Information & communication | 1998 |
| Textxs Limited | | 2005 |
| Teza Ltd | Wholesale & retail | 2023 |
| TFN Trading Ltd | Wholesale & retail | 2018 |
| Tfrancis Developments Limited | Real estate | 2018 |
| TG Archer Limited | Construction | 2019 |
| TG Scaffolding Services Limited | Construction | 2026 |
| TGB Properties Northampton Ltd | Real estate | 2026 |
| TGF OLE Expertise Ltd | Construction | 2017 |
| TGL 2024 Limited | Information & communication | 2019 |
| Tglo Ltd | Education | 2023 |
| TGM Elevators Limited | Manufacturing | 2024 |
| TGP Solutions (NE) Ltd | Construction | 2007 |
| Thaai Media UK Ltd | Manufacturing | 2023 |
| Thai TUK Ltd | Hospitality | 2019 |
| Thamby's Limited | Health & social care | 2013 |
| Thames Express Laundry and Drycleaning Ltd | Administrative & support | 2025 |
| Thamesway Publishing Limited | Information & communication | 2010 |
| Tharavad Music Band UK Limited | Information & communication | 2023 |
| That Undiscovered Country Ltd | Information & communication | 2013 |
| Thattukada Ltd | Wholesale & retail | 2021 |
| THB Developments Ltd | Real estate | 2023 |
| THC Homes Ltd | Manufacturing | 2020 |
| THE 22:23 Community Interest Company | Health & social care | 2025 |
| THE a Team Telecom Ltd | Construction | 2022 |
| THE Adhd Creative Hub CIC | Health & social care | 2025 |
| THE Admin Bureau Limited | Financial services | 1989 |
| THE Aflete Co Ltd | Wholesale & retail | 2023 |
| THE Andrology Company Limited | Health & social care | 2013 |
| THE Apertus Group Limited | Professional & scientific | 2016 |
| THE Art of Living Limited | Professional & scientific | 2023 |
| THE Art of Wood Limited | Manufacturing | 2017 |
| THE Artichoke Inn Ltd | Hospitality | 2022 |
| THE Ashby Clinic Ltd | Health & social care | 2018 |
| THE Association of Building Engineers | Other services | 1943 |
| THE Association of Trainers (Asot) Limited | Education | 2019 |
| THE Attic Room Design Limited | Manufacturing | 2008 |
| THE Auto Emporium Limited | Transport & logistics | 2024 |
| THE Aviator Hotel Limited | Hospitality | 1959 |
| THE Baby Reflux Lady Ltd | Education | 2017 |
| THE Baca Charity | Health & social care | 2008 |
| THE Bake House Management Company Limited | Households | 2001 |
| THE Bakers Recruiter Limited | Administrative & support | 2026 |
| THE Baking Forum Limited | Other services | 2022 |
| THE Bangla Company by P Ltd | Wholesale & retail | 2022 |
| THE Barnett School Limited | Education | 2026 |
| THE Basement Bakery Limited | Hospitality | 2023 |
| THE BAU Haus Management Company Ltd | Administrative & support | 2015 |
| THE Bead Store (U.K) Limited | Other services | 2023 |
| THE Bear Life Ltd | Arts & recreation | 2020 |
| THE Beauty Alliance International Limited | Manufacturing | 2018 |
| THE Beauty Barn (Northampton) Ltd | Other services | 2018 |
| THE Beauty Box Northampton Limited | Other services | 2022 |
| THE Beauty Room Academy Ltd | Education | 2022 |
| THE BED Store Hertfordshire Limited | Wholesale & retail | 2014 |
| THE Beer Garage Limited | Wholesale & retail | 2015 |
| THE Beez Healthcare Limited | Health & social care | 2021 |
| THE Bella Room Limited | Other services | 2020 |
| THE Beloved Blossoms Ltd | Real estate | 2024 |
| THE Belsteads Group Limited | Administrative & support | 2016 |
| THE Belsteads Retreat Limited | Health & social care | 2019 |
| THE Belsteads School Limited | Education | 2016 |
| THE Benedict Portal Ltd | Administrative & support | 2019 |
| THE Best Door Inc Limited | Other services | 2009 |
| THE Big Olive PUB Co Ltd | Hospitality | 2021 |
| THE Bike Sanctuary Ltd | Wholesale & retail | 2020 |
| THE Birth Base Ltd | Education | 2021 |
| THE Birth Uprising Ltd | Wholesale & retail | 2023 |
| THE Black Prince PUB Ltd | Hospitality | 2024 |
| THE Blacks Events Ltd | Hospitality | 2025 |
| THE Blizz African Restaurant Limited | Hospitality | 2023 |
| THE Bloom Room by Nina Ltd | Wholesale & retail | 2025 |
| THE Blowout Room Ltd | Other services | 2025 |
| THE Borderland Spirits Company Limited | Manufacturing | 2019 |