| Tekbase Limited | Information & communication | 1996 |
| Tekdrive Limited | Transport & logistics | 2008 |
| Tekmotiv Limited | Wholesale & retail | 2025 |
| Tekne Fitness Ltd | Arts & recreation | 2013 |
| Tekne Gymnastics Limited | Arts & recreation | 2008 |
| Tekne Juniors Ltd | Arts & recreation | 2017 |
| Teknoglass Solutions LLP | | 2014 |
| Tekuncle Ltd | Hospitality | 2025 |
| Tekvmax Limited | Construction | 2025 |
| Telebilling Limited | Administrative & support | 2004 |
| Telecoms XL Limited | Information & communication | 1998 |
| Telepathy Music Ltd | Information & communication | 2017 |
| Tellus Apparel Ltd | Wholesale & retail | 2024 |
| Telta Ltd | Wholesale & retail | 2023 |
| Temesis Limited | Education | 2010 |
| Temp ALL Staffing Group Ltd | Administrative & support | 2025 |
| Temp ALL Staffing Holdings Ltd | Financial services | 2022 |
| Temp ALL Staffing Ltd | Administrative & support | 2018 |
| Temple 90 Limited | Administrative & support | 2017 |
| Temple Court Chelmsford Limited | Real estate | 2016 |
| Temple Mead Management Company Limited | Households | 1988 |
| Temple of Sun Ltd | Real estate | 2023 |
| Templefields Management Company Limited | Households | 1991 |
| Templewood Investment Limited | Real estate | 2025 |
| TEN-12 Limited | Wholesale & retail | 2019 |
| Tenacity Wealth Management Limited | Financial services | 2014 |
| Tenant Management (9) Limited | Households | 2005 |
| Tendernest Care Ltd | Health & social care | 2025 |
| Tendring Central Company Limited | Construction | 2024 |
| Tendring Fabrications Ltd | Manufacturing | 2022 |
| Tendring Homes Ltd | Construction | 2021 |
| Tendring Hundred Farmers' Club | Other services | 1989 |
| Tendring Nursery Limited | Wholesale & retail | 2012 |
| Tendring Potato Suppliers Ltd | Wholesale & retail | 2022 |
| Tendring Primary Care Network Limited | Health & social care | 2023 |
| Tendring Travel Services Limited | Transport & logistics | 2026 |
| Tengiz Barbers Ltd | Other services | 2026 |
| Tenjris Limited | Professional & scientific | 2022 |
| Tenon Decorating Limited | Construction | 2003 |
| Tentastay Limited | Other services | 2017 |
| Teoneotrans Limited | Transport & logistics | 2025 |
| Teppich Limited | Extraterritorial | 2014 |
| Termhouse (1/24 Northgates) Management Limited | Households | 1977 |
| Termo-Clima Limited | Construction | 2013 |
| Tern Developments Limited | Construction | 2011 |
| Terr Solutions Ltd | Professional & scientific | 2024 |
| Terra Analytical UK Ltd | Construction | 2022 |
| Terra Official Limited | Wholesale & retail | 2020 |
| Terra Sports Limited | Extraterritorial | 2018 |
| Terracore Materials Ltd | Wholesale & retail | 2026 |
| Terry TEW Sound & Light Limited | Administrative & support | 1999 |
| Terson Holdings Limited | Financial services | 2022 |
| Terson Willow Tree Investments Limited | Construction | 2021 |
| TES 2000 Limited | Administrative & support | 1999 |
| Teskay Ltd | Health & social care | 2015 |
| Tess Care Solutions Limited | Wholesale & retail | 2018 |
| Tessera Credit Group LLP | | 2012 |
| Tessera Credit Services Limited | Financial services | 1989 |
| Tessier-Ashpool Limited | Health & social care | 2021 |
| Test and Connect Ltd | Construction | 2025 |
| Test Trader Ltd | Wholesale & retail | 2026 |
| Tetrus Group Holdings Limited | Financial services | 2021 |
| Tetrus Holdings Limited | Financial services | 2026 |
| Tevasis Limited | Professional & scientific | 2012 |
| Tevt Ltd | Administrative & support | 2024 |
| Texxon Limited | Construction | 2022 |
| TEY Fire Training Ltd | Public administration | 2025 |
| TEY Gardens LLP | | 2007 |
| TEY Grove Management Company Limited | Households | 2017 |
| TEY Skips Limited | Administrative & support | 2017 |
| TF Training & Assessing Limited | Construction | 2023 |
| TFM Homes Limited | Real estate | 2016 |
| TFP Storage Limited | Real estate | 2025 |
| TFS Investments Ltd | Real estate | 1994 |
| TG Catering Ltd | Hospitality | 2024 |
| TG Pet Care and Breeder Ltd | Agriculture & fishing | 2024 |
| TG Properties (Essex) Limited | Real estate | 2016 |
| TGA Mobility Limited | Manufacturing | 1998 |
| TGD Properties Limited | Real estate | 2024 |
| TGF Services Ltd | Real estate | 2021 |
| TGL Contracting Limited | Construction | 2017 |
| TGL Devco 1 Ltd | Construction | 2024 |
| TGL Futurebuild (Holdings) Limited | Financial services | 2018 |
| TGL Properties Limited | Construction | 2017 |
| Tgscanu Ltd | Construction | 2020 |
| TGW Consulting Limited | Professional & scientific | 2024 |
| TH Electrical Limited | Construction | 1998 |
| TH Gems and Jewellery Ltd | Wholesale & retail | 2024 |
| Thac Consulting Limited | Professional & scientific | 2022 |
| Thac Investments Limited | Real estate | 2019 |
| Thackray Commercial Plumbing and Heating Ltd | Construction | 2023 |
| Thai Colchester Limited | Hospitality | 2024 |
| Thaini Ltd | Health & social care | 2017 |
| Thames Media & Souvenirs Ltd | Wholesale & retail | 2019 |
| Thames RIB Experience Ltd | Transport & logistics | 2007 |
| Thameside Nature Park Ltd | Agriculture & fishing | 2010 |
| Thanushakudithipudi Limited | Information & communication | 2013 |
| Thasang Hyuol Ddhim (THD) Limited | Hospitality | 2015 |
| Thaxted Developments Limited | Construction | 2018 |
| Thaxted Real Estate Ltd | Real estate | 2026 |