| Tahir Investments Ltd | Real estate | 2017 |
| Tailor Made Solutions Limited | Administrative & support | 2006 |
| Take Note Publishing Limited | Manufacturing | 1994 |
| Take the Cake Limited | Manufacturing | 1994 |
| Talking Point Market Research Ltd | Professional & scientific | 2014 |
| TAM Leisure New Malden Limited | Wholesale & retail | 2006 |
| Tamarind Natural Products Limited | Wholesale & retail | 1999 |
| Tamil Heritage Society UK | Health & social care | 2023 |
| Tamworth Park Management Company (Mitcham) Limited | Real estate | 1991 |
| Tana Meinaa Properties Ltd | Real estate | 2024 |
| Tanacious Estates Ltd | Real estate | 2006 |
| Tanacious Limited | Other services | 2002 |
| Tanby Construction Limited | Construction | 1984 |
| Tanby Leisure Products Limited | Manufacturing | 1989 |
| Tandem Catering Ltd | Hospitality | 2002 |
| Tandridge Golf Club Limited | Arts & recreation | 2023 |
| Tanglewood Enterprises Ltd. | Real estate | 1999 |
| Tangoplace Limited | Households | 1989 |
| Tann Group Limited | Administrative & support | 2022 |
| Target Promotions Limited | Manufacturing | 1987 |
| Target Therapies Corporate Limited | Health & social care | 2023 |
| Target Therapies Franchise 1 Limited | Health & social care | 2023 |
| Tash Fuel Limited | Wholesale & retail | 2016 |
| Tasis Properties Limited | Construction | 1998 |
| Tasis the American School in England Limited | Education | 1981 |
| Tasis UK Limited | Education | 1981 |
| Taskdale Limited | Construction | 1999 |
| Taskgrove Limited | Professional & scientific | 1978 |
| Tasneem Consulting Ltd | Information & communication | 2017 |
| Tass Property Ltd | Real estate | 2020 |
| Taste of Jordan Limited | Wholesale & retail | 2004 |
| Tastingbuddy Limited | Extraterritorial | 2007 |
| Tasty Bread House Ltd | Manufacturing | 2012 |
| Tasweerkash Productions Ltd | Professional & scientific | 2022 |
| Tate (London) Limited | Information & communication | 2001 |
| Tate Technology Limited | Information & communication | 2003 |
| Tavern Court Management Limited | Households | 1989 |
| Tavira Consultants Limited | Financial services | 2007 |
| Tax Data Limited | Professional & scientific | 1996 |
| Taxaid Limited | Professional & scientific | 1993 |
| Taxi SRS Ltd | Transport & logistics | 2017 |
| Taya Purley Ltd | Hospitality | 2020 |
| Taylor & England Ltd | Administrative & support | 2024 |
| Taylor Commercial Repairs Limited | Wholesale & retail | 2001 |
| Tayvulin Ltd | Professional & scientific | 2019 |
| TBB Building Ltd | Construction | 2016 |
| TC Carpets & Flooring Limited | Wholesale & retail | 1995 |
| TCS Computer Sales Limited | Professional & scientific | 1990 |
| TDN Consulting Limited | Information & communication | 2005 |
| TDR Solutions Limited | Other services | 2005 |
| Team Animation Limited | Professional & scientific | 2001 |
| Techassist UK Ltd | Information & communication | 2007 |
| Techbyte Limited | | 1988 |
| Technica Solutions Limited | Information & communication | 2004 |
| Technik Recruitment Limited | Real estate | 1998 |
| Technology Resources Limited | Other services | 2003 |
| Technophone Limited | Other services | 1996 |
| Techtools (Morden) Limited | Wholesale & retail | 1982 |
| Tecnica Building Services Ltd | Construction | 1998 |
| TED Adams Trust Limited | Health & social care | 2004 |
| TED Neale Carpentry & Handyman Ltd | Manufacturing | 2022 |
| Teddington Harbour Limited | Arts & recreation | 1995 |
| Teddington Harbour Yacht Club Limited | Administrative & support | 1996 |
| Telcheck Limited | Information & communication | 1993 |
| Telemark Management Services Limited | Professional & scientific | 1999 |
| Telemark Trading Limited | Wholesale & retail | 1989 |
| Teleplex Limited | Manufacturing | 1983 |
| Teleservice (Carshalton) Limited | | 1959 |
| Telford Technical Research Limited | Manufacturing | 1988 |
| Temple Aviation Limited | | 1987 |
| Temple Yoga Ltd | Arts & recreation | 2023 |
| Templecare Limited | Extraterritorial | 1995 |
| Tempra Consulting Services Ltd | Professional & scientific | 1997 |
| TEN Beresford Limited | Households | 2005 |
| TEN Marlborough Road Limited | Households | 1982 |
| Tenacity Consulting Ltd | Professional & scientific | 2002 |
| Tenchbond Limited | Information & communication | 1985 |
| Tenchleys Investments Limited | Real estate | 1993 |
| Tenscare Limited | Wholesale & retail | 1993 |
| Tensdirect Limited | Wholesale & retail | 1998 |
| Tepco Computers Limited | | 1983 |
| Terabyte Solutions Limited | Professional & scientific | 2004 |
| Teralis Ltd. | Construction | 2004 |
| Terra Rossa Jordan Limited | Wholesale & retail | 2004 |
| Terry Miles Consulting Limited | Other services | 2006 |
| Testum Ltd | Information & communication | 2022 |
| TFS Handling (UK) Ltd | Transport & logistics | 2003 |
| TFT Consulting Limited | Administrative & support | 2008 |
| Thaalam Productions Limited | Information & communication | 2008 |
| Thais "R" US Limited | Wholesale & retail | 2000 |
| Thames Christian School | Education | 2000 |
| Thames Ditton Sports and Squash Club Limited | Arts & recreation | 1977 |
| Thames Hill Building and Property Services Limited | Construction | 2010 |
| Thames Skiff Hire Limited | Administrative & support | 2007 |
| Thames Valley Pneumatic Limited | Manufacturing | 1991 |
| Thames Valley Retirement Homes Limited | Real estate | 1984 |
| Thater Media Limited | Professional & scientific | 2006 |
| Thayne Electrical Services Limited | Construction | 2004 |
| THE 23 Cardigan Road Residents Association Limited | Households | 1999 |
| THE Accessible Digital Documents Company Ltd | Information & communication | 2008 |