| Twentyci Data Limited | Other services | 2006 |
| Twentyci Limited | Information & communication | 2009 |
| Twentyci PNM Limited | Information & communication | 2013 |
| Twentycraft Limited | Financial services | 2008 |
| Twiga Security Ltd | Administrative & support | 2021 |
| Twigden Consultancy Limited | Professional & scientific | 2012 |
| Twilliams Consultancy Limited | Administrative & support | 2019 |
| Twin Design Branding Ltd | Professional & scientific | 2021 |
| Twin Engineering Limited | Manufacturing | 2004 |
| Twin Rivers Care Ltd | Health & social care | 2022 |
| Twinkle Little Stars Nursery Ltd | Health & social care | 2022 |
| Twinkle Twinkle Star Ltd | Education | 2026 |
| Twinprime Plumbing & Heating Ltd | Construction | 2026 |
| Twintech Services Limited | Information & communication | 2000 |
| Twisted Noise Troupe Limited | Arts & recreation | 2018 |
| Twisted Tree Surgery Ltd | Other services | 2014 |
| Twiston Davies Equine Ltd | Arts & recreation | 2018 |
| Twizel Close Management Company Limited | Real estate | 2006 |
| Twizell Property Ltd | Real estate | 2022 |
| Twkb Limited | Professional & scientific | 2008 |
| Two Hearts Ltd | Other services | 2022 |
| Two Mile ASH Community Centre | Arts & recreation | 2000 |
| Two Mile ASH Food & Wine Limited | Wholesale & retail | 2012 |
| Two Mile ASH School Limited | Extraterritorial | 2016 |
| Two Signatures Ltd | Wholesale & retail | 2020 |
| Two Squared Creative Limited | Professional & scientific | 2018 |
| Two Tees Consultancy Limited | Professional & scientific | 2012 |
| Two Tees Consultants Ltd | Professional & scientific | 2015 |
| Two Tees Healthcare Services Limited | Health & social care | 2023 |
| Two Tees Properties Limited | Real estate | 2023 |
| Twofour Property Management Ltd | Real estate | 2024 |
| TWP Consultancy Ltd | Professional & scientific | 2021 |
| TWP Solutions Ltd | Professional & scientific | 2010 |
| TXB Ltd | Professional & scientific | 2024 |
| TXH Consulting Ltd | Other services | 2016 |
| TXM Consult Digital Limited | Professional & scientific | 2010 |
| TXM Consult Limited | Professional & scientific | 2017 |
| TXM Group Limited | Financial services | 2019 |
| TXM Healthcare Limited | Administrative & support | 2010 |
| TXM Management Limited | Professional & scientific | 2014 |
| TXM Recruit Ltd | Administrative & support | 2005 |
| TY Hospitality Limited | Hospitality | 2017 |
| Tyburn Merchants Ltd | Real estate | 2022 |
| Tybyano Transport Ltd | Transport & logistics | 2017 |
| Tyce Property Ltd | Real estate | 2024 |
| Tyche Digital Ltd | Information & communication | 2023 |
| Tycol Properties Ltd | Real estate | 2026 |
| Tycoon Services Ltd | Administrative & support | 2017 |
| Tydell Investments Limited | Real estate | 1983 |
| Tyelong Limited | Professional & scientific | 2001 |
| Tyman Consultancy Services Limited | Health & social care | 2008 |
| Tyntel Services Ltd | Transport & logistics | 2015 |
| Tyre & Exhaust Care (Stony Stratford) Limited | | 1976 |
| Tyre Donut UK Ltd | Wholesale & retail | 2025 |
| Tyres (Northampton) Commercial LLP | | 2003 |
| TYS Insight Limited | Other services | 2026 |
| TZ Goods Limited | Administrative & support | 2024 |
| TZM Consultants Ltd | Other services | 2012 |
| TZM International Limited | Administrative & support | 2026 |
| TZM Investments Limited | Real estate | 2015 |
| T’Sbeautyproducts Limited | Wholesale & retail | 2026 |
| U Khan Holdings Limited | Financial services | 2022 |
| U&A Enterprise Limited | Health & social care | 2010 |
| U-Homes Estate Ltd | Real estate | 2019 |
| UAQ Limited | Wholesale & retail | 2023 |
| UB Infrastructure Ltd | Manufacturing | 2023 |
| Uber Training Solutions Limited | Information & communication | 2015 |
| Uberhub Strand Ltd | Professional & scientific | 2015 |
| Uberstar Limited | Wholesale & retail | 2012 |
| Ubiquity Ltd | Administrative & support | 2017 |
| Ubuntu OY Ltd | Wholesale & retail | 2026 |
| UBX Franchise Limited | Professional & scientific | 2021 |
| Ucan-Do-It Limited | Information & communication | 2013 |
| UCC Coffee UK Limited | Wholesale & retail | 1987 |
| Uchi Developments Limited | Real estate | 2021 |
| Uclick Services Ltd | Transport & logistics | 2020 |
| Ucplus Limited | Health & social care | 2017 |
| Uday- Business Solutions Limited | Information & communication | 2012 |
| Uddin Investments MK Ltd | Real estate | 2025 |
| Uddin Real Estate Ltd | Real estate | 2020 |
| Udemy Japan Limited | Information & communication | 2014 |
| Udrive Taxi Hire Ltd | Administrative & support | 2025 |
| UFM45EG Limited | Construction | 2022 |
| Ufnmo Limited | Real estate | 2024 |
| UG Locum Consultants Limited | Health & social care | 2012 |
| Ugly Duck Creative Ltd | Professional & scientific | 2019 |
| Ugona Limited | Health & social care | 2022 |
| UIG Hotel Ltd | Hospitality | 2013 |
| Ujhasuma Africa CIC | Education | 2025 |
| UK (Edenor) International Trading Co., Ltd. | Manufacturing | 2025 |
| UK 11 Support Services Limited | Health & social care | 2024 |
| UK AI Events Limited | Administrative & support | 2025 |
| UK Angling Ltd | Wholesale & retail | 2023 |
| UK Astronomy Limited | Education | 2016 |
| UK Auto Exchange Ltd | Wholesale & retail | 2024 |
| UK Auto Parts Limited | Wholesale & retail | 2013 |
| UK Aviation Consulting Ltd | Extraterritorial | 2023 |
| UK Bakshi Ltd | Information & communication | 2013 |
| UK Beach Tour Ltd | Arts & recreation | 2018 |
| UK Biocentre Limited | Professional & scientific | 2011 |