| THE Willow Barbers Ltd | Other services | 2022 |
| THE Willows (Kentford) Management Company Limited | Households | 2019 |
| THE Wine Company (UK) Ltd | Wholesale & retail | 2014 |
| THE Wine Company Group Limited | Administrative & support | 2016 |
| THE Wishing Barn Limited | Information & communication | 2025 |
| THE Wivenhoe Fish Company Limited | Wholesale & retail | 2019 |
| THE Woman’S Career Ladder Limited | Professional & scientific | 2025 |
| THE Woodlands (Ickleford) Management Company Limited | Households | 2025 |
| THE Workers Beer Company Limited | Extraterritorial | 2007 |
| THE Workshop Hair Ltd | Other services | 2013 |
| THE Worship Company Ltd | Professional & scientific | 2019 |
| THE Worship Company Publishing Limited | Information & communication | 2020 |
| THE Write Impression LLP | | 2009 |
| THE3DGARDENER Ltd | Professional & scientific | 2020 |
| Theatre Staff Ltd | Health & social care | 2023 |
| Theatricool Limited | Arts & recreation | 2014 |
| Thecherrytreeinn Ltd | Hospitality | 2023 |
| Thedropzone Ltd | Wholesale & retail | 2025 |
| Theerdana Limited | Wholesale & retail | 2026 |
| Thefatcat Holdings Ltd | Financial services | 2014 |
| Thegnomecafe Ltd | Hospitality | 2021 |
| Thegreyhoundpub Ltd | Hospitality | 2016 |
| Thela Jets Ltd | Transport & logistics | 2024 |
| Them Apples Limited | Information & communication | 2002 |
| Themulla LLP | | 2026 |
| Theoberry Limited | Real estate | 1979 |
| Theory Training Solutions Limited | Information & communication | 2009 |
| Theosis Consultancy Import-Export & Business Development Ltd | Wholesale & retail | 2021 |
| Theoyster Limited | Hospitality | 2022 |
| Therma-Floor Underfloor Heating Ltd | Construction | 2020 |
| Thermix UK Ltd | Manufacturing | 2015 |
| Thetaconsultingservices Limited | Information & communication | 2022 |
| Thetickettrolley Ltd | Other services | 2017 |
| Things to DO in Business Franchises Ltd | Administrative & support | 2020 |
| Things to DO in Limited | Administrative & support | 2014 |
| Think Live Ltd | Information & communication | 2021 |
| Think Radio Ltd | Manufacturing | 2024 |
| Think Therapy 1ST Limited | Health & social care | 2012 |
| Think Therapy Holdings Limited | Financial services | 2023 |
| Thinksay Creative Communications Ltd | Professional & scientific | 2014 |
| Thirst Headhunt Recruitment Limited | Administrative & support | 2014 |
| This IS Fever Limited | Information & communication | 2015 |
| Thisfitcrew Limited | Arts & recreation | 2020 |
| THISIS30 Ltd | Professional & scientific | 2013 |
| Thistle and Rose Natural Skincare Limited | Manufacturing | 2021 |
| Thistlelark Ltd | Professional & scientific | 2025 |
| Thomas & Joseph Limited | Health & social care | 2013 |
| Thomas Ellis Engineering Holdings Limited | Financial services | 2017 |
| Thomas Ellis Engineering Limited | Manufacturing | 1970 |
| Thomas Walker CAD Services Ltd | Construction | 2018 |
| Thomaselectical Ltd | Construction | 2026 |
| Thompson & Butler Ltd | Energy | 2011 |
| Thompson Drylining Colchester Limited | Construction | 2023 |
| Thompson Reid Limited | Professional & scientific | 2017 |
| Thompson Smith & Puxon (Secretarial Services) Limited | Extraterritorial | 1992 |
| Thompson Smith and Puxon LLP | | 2025 |
| Thompson-Smith (Colchester) Limited | Construction | 2011 |
| Thompsons Office of Accounts Limited | Information & communication | 2008 |
| Thorcross Builders Limited | Construction | 1966 |
| Thorington Joinery Ltd | Construction | 2016 |
| Thornbury House Consultants Ltd | Professional & scientific | 2025 |
| Thornecroft Ltd | Construction | 2024 |
| Thornfield Court RTM Company Limited | Households | 2009 |
| Thornfleet Investments Ltd | Real estate | 2018 |
| Thornfleet Limited | Construction | 2026 |
| Thornton and Reeves Ltd | Construction | 2015 |
| Thornwood Solutions Limited | Administrative & support | 2002 |
| Thorny Devil Productions Ltd | Information & communication | 2013 |
| Thorpe Green Equestrian Centre Ltd | Other services | 2013 |
| Thorpe Green Farm Ltd | Agriculture & fishing | 2021 |
| Thorpe Horseboxes Limited | Manufacturing | 2007 |
| Thorpe Leisure Supplies Limited | Wholesale & retail | 2012 |
| Thorpe Vehicle Services Limited | Wholesale & retail | 2012 |
| Thorrington Mill Contracting Ltd | Agriculture & fishing | 2006 |
| Thorrington Stores Ltd | Wholesale & retail | 2011 |
| Thoughts and Mace Investments Ltd | Real estate | 2025 |
| Thread and Dandy Limited | Manufacturing | 2023 |
| Thread Consultants Ltd | Professional & scientific | 2009 |
| Three Counties Fireplaces Limited | Administrative & support | 2010 |
| Three Oaks Investments Ltd | Real estate | 2025 |
| Threeholders Limited | Real estate | 2003 |
| Thrift Farm Holdings Limited | Agriculture & fishing | 2019 |
| Thrive Gyms Ltd | Arts & recreation | 2022 |
| Thrive With Food Limited | Health & social care | 2026 |
| Through IT ALL Consultancy Ltd | Health & social care | 2023 |
| Throw Creative Ltd | Information & communication | 2021 |
| Thrower Training Ltd | Education | 2025 |
| Thrunsco Ltd | Financial services | 2016 |
| THS Essex Ltd | Transport & logistics | 2015 |
| THS Sales Ltd | Agriculture & fishing | 2024 |
| Thsoftware Ltd | Information & communication | 2020 |
| Thunderbird Solutions Limited | Information & communication | 2025 |
| Thurmans Grove Residents Management Company Limited | Real estate | 2016 |
| Thyme Building Consultancy Limited | Professional & scientific | 2010 |
| Thyroid UK | Health & social care | 2007 |
| Tiap Limited | Real estate | 2021 |
| Tickenhall Residents Association Limited | Households | 1992 |
| Ticketdrop Ltd | Wholesale & retail | 2023 |
| Tidal Building Solutions Ltd | Construction | 2025 |
| Tiddles Day Nursery Limited | Health & social care | 2023 |