| Tmoet Limited | Professional & scientific | 2013 |
| TMR Carpentry Limited | Construction | 2014 |
| Tmrc Medical Limited | Health & social care | 2019 |
| TMT CAM Law Ltd | Professional & scientific | 2019 |
| Tm’S World Ltd | Other services | 2025 |
| Tneytitne Limited | Manufacturing | 2021 |
| TNQ Medical Limited | Health & social care | 2021 |
| TOA Technology Co., Ltd | Extraterritorial | 2020 |
| Toadrage Leisure Limited | Hospitality | 2019 |
| Toadrage Limited | Agriculture & fishing | 2001 |
| Toadrage Media Ltd | Extraterritorial | 2013 |
| Toast on Cheese Limited | Hospitality | 2021 |
| Toast Trading Ltd | Wholesale & retail | 2020 |
| Tobilac Property Management Ltd | Real estate | 2022 |
| Tobit Curteis Associates LLP | | 2008 |
| Toby Cowell Property Ltd | Real estate | 2024 |
| Toby Goodwin-Smith Ltd | Administrative & support | 2025 |
| TOC Trimming Ltd | Manufacturing | 2017 |
| Todd Research Limited | Manufacturing | 1950 |
| Todev UK Ltd | Construction | 2006 |
| Toerien Holdings Ltd | Financial services | 2024 |
| Tofivet Pet Supplies UK Ltd | Wholesale & retail | 2026 |
| TOG Property Holdings Limited | Financial services | 2025 |
| TOG Property Limited | Real estate | 2025 |
| Togeza Healthcare Limited | Health & social care | 2023 |
| Tokenovate Limited | Information & communication | 2022 |
| Toksell Ltd | Wholesale & retail | 2025 |
| Tolemy BIO Ltd. | Information & communication | 2024 |
| Tollaris Ltd | Information & communication | 2025 |
| Tolux Limited | Real estate | 2005 |
| TOM Composites Leader Ltd | Manufacturing | 2022 |
| TOM Composites Ltd | Manufacturing | 2020 |
| TOM Haylock & Co.Limited | Agriculture & fishing | 1951 |
| TOM Jack Ltd | Professional & scientific | 2026 |
| TOM Noble Composites Ltd | Manufacturing | 2021 |
| TOM Peach Heart Co., Ltd. | Wholesale & retail | 2025 |
| TOM Perry Films Ltd | Information & communication | 2022 |
| TOM Professional Services Limited | Health & social care | 2019 |
| TOM Roach Consulting Limited | Professional & scientific | 2020 |
| TOM Robinson Sprays Limited | Agriculture & fishing | 2014 |
| Toma Engineering Ltd | Manufacturing | 2026 |
| Tomas Kitchens Plus Ltd | Wholesale & retail | 2001 |
| Tomeo Aviation Ltd | Manufacturing | 2024 |
| TOMMY95 Ltd | Wholesale & retail | 2025 |
| Tommyhuafee Co., Ltd. | Wholesale & retail | 2025 |
| Toms Kitchen CCS Ltd | Hospitality | 2010 |
| Tomson & Lendrum Limited | Real estate | 1946 |
| Tone's Property Services Ltd | Administrative & support | 2022 |
| Tonev 91 Ltd | Transport & logistics | 2023 |
| Tongcheng Xinjian Hardware Tools Co., Ltd | Wholesale & retail | 2024 |
| Tongli Trading Co., Ltd | Wholesale & retail | 2023 |
| Tongxiang Winney Machinery Co., Ltd | Extraterritorial | 2015 |
| Toniame Ltd | Manufacturing | 2025 |
| Tonny Builder Limited | Construction | 2023 |
| Tonsim Electronic Co., Ltd | Extraterritorial | 2015 |
| Tony Adcock Limited | Professional & scientific | 1991 |
| Tony Osborne FD Ltd | Professional & scientific | 2024 |
| Tonyjuniper.Com Limited | Professional & scientific | 2012 |
| TOO Cool Ltd | Administrative & support | 2000 |
| Toolpool Ltd | Administrative & support | 2025 |
| Tooth Station Ltd | Health & social care | 2017 |
| Toothlens Limited | Information & communication | 2024 |
| Top 1 Group Limited | Wholesale & retail | 2025 |
| Top Banana Limited | Financial services | 2018 |
| Top BBQ Industrial Co., Ltd | Wholesale & retail | 2022 |
| Top Class Ltd | Wholesale & retail | 2025 |
| Top Eco Cleaning Services Ltd | Administrative & support | 2025 |
| Top Gear Shipping (Shenzhen) Co., Limited | Wholesale & retail | 2025 |
| Top Nails Cambridge Ltd | Other services | 2020 |
| Top Rebels Ltd | Wholesale & retail | 2023 |
| Top Spin Tennis (Retail) Ltd | Administrative & support | 2025 |
| Top Star Industry Limited | Wholesale & retail | 2017 |
| Top Transfer Cambridge Ltd | Transport & logistics | 2023 |
| Topdo Limited | Information & communication | 2026 |
| TOPH4 Limited | Financial services | 2025 |
| Topiary Residents Company Limited(The) | Households | 1968 |
| Toplines Limited | Other services | 2002 |
| Topologi Limited | Manufacturing | 2026 |
| Topologica Ltd | Information & communication | 2024 |
| Toprak Maya Ltd | Hospitality | 2022 |
| Toptier Smart Repairs Ltd | Wholesale & retail | 2026 |
| Toreet Medical Limited | Health & social care | 2025 |
| Tornado Cleaning Management Ltd | Professional & scientific | 2022 |
| Torque and Beyond Aviation Support Ltd | Manufacturing | 2025 |
| Torrent Partners Limited | Information & communication | 2009 |
| Torsea Properties Ltd | Real estate | 2012 |
| TOT EI Limited | Information & communication | 2015 |
| TOT LOT Club Ltd | Health & social care | 2020 |
| Total Access & Security Limited | Construction | 2019 |
| Total Concept Scenery Ltd | Construction | 2021 |
| Total Facility Management Limited | Construction | 2013 |
| Total Project Engineering Limited | Real estate | 1984 |
| Totally Marketing Limited | Real estate | 2005 |
| Totem Semiconductor Limited | Professional & scientific | 1996 |
| Touch of Ginger Holdings Limited | Financial services | 2025 |
| Tourington Ltd | Professional & scientific | 2021 |
| Tourism Media Limited | Financial services | 2015 |
| Towards Victory Ltd | Wholesale & retail | 2025 |
| Towcester Grange (Towcester) Residents Management Company Limited | Households | 2017 |
| Tower House Wealth Management Limited | Professional & scientific | 1995 |