| Terralex Solutions Ltd | Information & communication | 2019 |
| Terrapin Global Limited | Information & communication | 2021 |
| Terx Limited | Wholesale & retail | 2024 |
| Tescon Development Ltd | Real estate | 2019 |
| Test Steps Solutions Ltd | Information & communication | 2022 |
| Testime Limited | Professional & scientific | 2011 |
| TEX Weave Limited | Manufacturing | 2025 |
| Texas Grill House Ltd | Hospitality | 2022 |
| Texas Transport Ltd | Transport & logistics | 2025 |
| Texdales Glorious Limited | Professional & scientific | 2019 |
| Texmod Holdings Limited | Manufacturing | 2019 |
| Texora Innovations Limited | Wholesale & retail | 2025 |
| Tezoragency Ltd | Wholesale & retail | 2021 |
| TF Healthcare Ltd | Public administration | 2021 |
| TF Services Limited | Professional & scientific | 2003 |
| TFM Innovations Limited | Other services | 2011 |
| Tfom Ltd | Real estate | 2018 |
| TFS Logistics Limited | Transport & logistics | 1999 |
| TG Traders Limited | Wholesale & retail | 2025 |
| Tgcloud Limited | Professional & scientific | 2025 |
| TGS Aviation Solutions Ltd | Transport & logistics | 2025 |
| TH Investment Group Limited | Wholesale & retail | 2025 |
| THA Slough Tuck Store Limited | Wholesale & retail | 2025 |
| Thaggu KE Laddu Limited | Hospitality | 2022 |
| Thahirs Limited | Real estate | 2022 |
| Thai Railways Limited | Hospitality | 2022 |
| Thakre Capital Ltd | Real estate | 2026 |
| Thame Taxis & Chinnor Cabs Ltd | Transport & logistics | 2017 |
| Thames Beauty Centre Limited | Administrative & support | 2007 |
| Thames Concrete Ltd | Manufacturing | 2022 |
| Thames Executive Transfers Ltd | Transport & logistics | 2025 |
| Thames Haulage Ltd | Transport & logistics | 2022 |
| Thames Logistics Ltd | Transport & logistics | 2026 |
| Thames Regional Projects Ltd | Professional & scientific | 2026 |
| Thames Telecom Limited | Information & communication | 1993 |
| Thames Tiles & Stone Ltd | Construction | 2025 |
| Thames Trading Ltd | Wholesale & retail | 2026 |
| Thames Traditional Boat Rally | Education | 2002 |
| Thames Valley Business Excellence Awards Ltd | Other services | 2003 |
| Thames Valley Chamber of Commerce and Industry | Other services | 1949 |
| Thames Valley Economic Development Company Limited | Administrative & support | 2026 |
| Thames Valley Economic Partnership Limited | Administrative & support | 2026 |
| Thames Valley Engineering Limited | Professional & scientific | 2017 |
| Thames Valley Enterprise Partnership Limited | Administrative & support | 2026 |
| Thames Valley Facilities Ltd | Construction | 2021 |
| Thames Valley Family Mediation Service Ltd | Administrative & support | 2005 |
| Thames Valley Garage Limited | Wholesale & retail | 2003 |
| Thames Valley Growth Company Limited | Administrative & support | 2026 |
| Thames Valley Insulation Limited | Construction | 2016 |
| Thames Valley Language Assessment Centre Ltd | Education | 2025 |
| Thames Valley Recovery Limited | Other services | 2023 |
| Thames Valley Refinishing Limited | Manufacturing | 2013 |
| Thames Valley Steel Detailing Ltd | Professional & scientific | 2015 |
| Thames Valley Telecom Ltd | Wholesale & retail | 2018 |
| Thames Valley Temps Ltd | Administrative & support | 2020 |
| Thames Valley Tennis C.I.C. | Arts & recreation | 2020 |
| Thames Valley Trading Limited | Financial services | 2026 |
| Thames Valley Training Ltd | Other services | 2003 |
| Thames Valley Transport Limited | | 1987 |
| Thames View Estates Limited | Real estate | 2020 |
| Thamesflux Web Services Ltd | Information & communication | 2026 |
| Thandi RS Developments Limited | Construction | 2026 |
| Thara Lettings Ltd | Real estate | 2012 |
| That's Mine Ltd | Real estate | 2026 |
| That's Mine Property Ltd | Real estate | 2019 |
| That's Mine Transport Ltd | Transport & logistics | 2026 |
| That's the Way Ltd | Construction | 2015 |
| Thattara Limited | Health & social care | 2019 |
| Thcd Limited | Health & social care | 2025 |
| Thdreamcleaners Ltd | Administrative & support | 2025 |
| THE Abdeali Trustee Company Limited | Other services | 2003 |
| THE Abinger Cookery School Limited | Other services | 2020 |
| THE Acai Club 1 Ltd | Hospitality | 2025 |
| THE Acai Club 2 Ltd | Hospitality | 2025 |
| THE Acai Club 3 Ltd | Hospitality | 2025 |
| THE Acai Club 4 Ltd | Hospitality | 2025 |
| THE Acai Club Ltd | Hospitality | 2023 |
| THE Accounttx Ltd | Extraterritorial | 2012 |
| THE Address Group Ltd | Professional & scientific | 2015 |
| THE Address Management Ltd | Professional & scientific | 2015 |
| THE Address Property Ltd | Real estate | 2018 |
| THE Aden Group Network Ltd | Professional & scientific | 2026 |
| THE AKD Group of Companies Limited | Financial services | 2024 |
| THE Aleph Circle Ltd | Extraterritorial | 2013 |
| THE Alexandra Property Partnership Limited | Real estate | 2011 |
| THE Amwell Care Home Limited | Health & social care | 2014 |
| THE ARB Clinic Ltd | Other services | 2025 |
| THE Arbib Education Trust | Education | 2005 |
| THE ARK Intiative CIC | Education | 2025 |
| THE Art of Education Limited | Education | 2016 |
| THE Association of International Certified Practising Accountants | Education | 2013 |
| THE Barbers Zone Ltd | Other services | 2018 |
| THE Barton Meat Company Limited | Wholesale & retail | 2004 |
| THE Berkshire Coin Company Limited | Wholesale & retail | 2025 |
| THE Best House Solutions Ltd | Construction | 2016 |
| THE Black & White Coffee Company Limited | Wholesale & retail | 1999 |
| THE Blind Phoenix Ltd | Wholesale & retail | 2019 |
| THE Bootleg Sixties NOT Fading Away LLP | | 2007 |
| THE Bowl & Spork Ltd | Hospitality | 2020 |
| THE Building Consultant Group. Ltd | Professional & scientific | 2024 |