| Thakral Services Ltd | Construction | 2025 |
| Thames Meadow Residents Association Limited | Households | 1986 |
| Thames Roofing and Building Limited | Other services | 2021 |
| Thames Side Brewery Ltd | Manufacturing | 2015 |
| Thames UK Group Limited | Water & waste | 2025 |
| Thames Valley Design and Print Limited | Manufacturing | 2007 |
| Thames Valley Properties UK Limited | Real estate | 2004 |
| Thameside (Staines) Management Company Limited | Households | 1970 |
| Thameside Engineering (Staines) Limited | Wholesale & retail | 2011 |
| Thameside Industrial Coating Services Ltd | Real estate | 2021 |
| Thameside Industrial Coatings Limited | Extraterritorial | 2019 |
| Thameside Solutions Ltd | Water & waste | 2025 |
| Thapa & Partners Ltd | Wholesale & retail | 2023 |
| THE Aeon Aesthetics Ltd. | Manufacturing | 2024 |
| THE Autumn Walk Management Company Limited | Households | 1990 |
| THE Beauty Chef UK Limited | Wholesale & retail | 2016 |
| THE Breathable Lime Plastering Company Limited | Construction | 2023 |
| THE Bright College Limited | Education | 2018 |
| THE Canford Partnership Limited | Extraterritorial | 1996 |
| THE Capstone Management Company Limited | Real estate | 2004 |
| THE Carpet Gallery (Staines) Limited | Wholesale & retail | 2012 |
| THE Centre Properties (UK) Limited | Real estate | 2013 |
| THE Commercial Retail Solution Ltd | Other services | 2015 |
| THE Creators Group Ltd | Professional & scientific | 2025 |
| THE Dartsmith Ltd | Manufacturing | 2025 |
| THE DEN Cafe Ltd | Hospitality | 2026 |
| THE DHL UK Foundation | Administrative & support | 1988 |
| THE Enclosure Company Ltd | Extraterritorial | 2016 |
| THE Every Trust | Education | 2018 |
| THE General Gardening Company Ltd | Households | 2024 |
| THE George Institute for Global Health (UK) | Professional & scientific | 2008 |
| THE George Wraysbury Ltd | Hospitality | 2025 |
| THE Grange (Staines) Limited | Households | 1999 |
| THE Green Corridor | Education | 2001 |
| THE Greenwich MK Limited | Wholesale & retail | 2017 |
| THE Hamilton EGG Company Limited | Financial services | 2020 |
| THE Hartstone Group Limited | Professional & scientific | 1985 |
| THE Headache Centre Limited | Health & social care | 2011 |
| THE Hive Pharmacy Limited | Wholesale & retail | 2009 |
| THE Home Company Group Ltd | Real estate | 2020 |
| THE House Cleaning Company Ltd | Administrative & support | 2021 |
| THE HR Firm Ltd | Administrative & support | 2021 |
| THE Independent Networks Association | Other services | 2008 |
| THE Irreplaceable Advisory Group Limited | Other services | 2016 |
| THE Lifting Club TLC Ltd | Arts & recreation | 2026 |
| THE Lodge Stanwell Heathrow Limited | Hospitality | 2025 |
| THE London School of Coffee Limited | Education | 2004 |
| THE Mexicanos Restaurant Ltd | Hospitality | 2023 |
| THE Monday Loft Ltd | Information & communication | 2023 |
| THE Moorings (Fradley) Management Company Limited | Households | 2026 |
| THE Moorings Abbey Chase Limited | Households | 1992 |
| THE New EGG Company Limited | Manufacturing | 2019 |
| THE Nomad Stop Ltd | Hospitality | 2024 |
| THE Old Bakery Freehold Limited | Households | 2001 |
| THE Oxygen Temple Limited | Other services | 2025 |
| THE Post House Ltd | Real estate | 2022 |
| THE Red Shop Ltd | Wholesale & retail | 2017 |
| THE Sash King Ltd | Construction | 2021 |
| THE Silver Oak Consultancy Ltd | Information & communication | 2018 |
| THE Sizzle Squad Limited | Hospitality | 2025 |
| THE Social Drive Ltd | Information & communication | 2026 |
| THE Swing Revue Ltd | Arts & recreation | 2016 |
| THE Visual Safari Design Group Limited | Professional & scientific | 2008 |
| THE Visual Safari Marketing Limited | Extraterritorial | 2008 |
| THE Visual Safari Web Design Limited | Extraterritorial | 2008 |
| THE Willows Staines Limited | Hospitality | 2013 |
| THE Woodpecker Inn Ltd | Hospitality | 2004 |
| Thepeakyburgers Limited | Hospitality | 2025 |
| Therakos (UK), Ltd | Financial services | 2012 |
| Thibaut UK Limited | Extraterritorial | 2015 |
| Thimbletack Ltd | Wholesale & retail | 2022 |
| Thingtrax Limited | Information & communication | 2015 |
| Thistlecraft Welding Ltd | Manufacturing | 2018 |
| Thomas Dream House Construction Limited | Extraterritorial | 2023 |
| Thomas Smith UK Ltd | Transport & logistics | 2025 |
| Thrive Global Consultancy Ltd | Financial services | 2020 |
| Thunderwolf Ltd. | Information & communication | 2019 |
| Tiles Tools & Timber Ltd | Transport & logistics | 2018 |
| Tilesline Ltd | Construction | 2026 |
| Tilly Flynn’S Ltd | Hospitality | 2022 |
| Timeless Prop Hire Ltd | Information & communication | 2025 |
| Timsway MOT & Refurb Ltd | Wholesale & retail | 2025 |
| Tineyfeet Ltd | Health & social care | 2024 |
| Tinkerbeau Ltd | Other services | 2024 |
| Tiny Temptations Limited | Hospitality | 2025 |
| Tiptrans Eka-Ste Ltd | Transport & logistics | 2019 |
| Titan MX & ATV Limited | Wholesale & retail | 2020 |
| Titanedge Ltd | Wholesale & retail | 2025 |
| Titans Taekwondo Limited | Arts & recreation | 2023 |
| TJ & SON Bespoke Joinery Limited | Construction | 2024 |
| TKR Bradford Limited | Hospitality | 2025 |
| TKS Services Limited | Administrative & support | 2024 |
| TLC Logistics Limited | Transport & logistics | 2024 |
| TLC Will Services Limited | Professional & scientific | 2015 |
| TNK Spark Limited | Wholesale & retail | 2026 |
| Tongue 'N' Cheek Productions Ltd | Arts & recreation | 2017 |
| Tonic Vitae Ltd | Health & social care | 2026 |
| Topcart Ltd | Wholesale & retail | 2025 |
| Toshiba Europe Limited | Manufacturing | 1990 |
| Toshiba of Europe Limited | Administrative & support | 1997 |