| TRB Chemedica (UK) Limited | Wholesale & retail | 2001 |
| Trcoxy Ltd | Financial services | 2024 |
| Tread-X Tyres Limited | Wholesale & retail | 2014 |
| Treadcare Tyre Services Ltd | Administrative & support | 2009 |
| Treadstone Investments Limited | Construction | 2017 |
| Treen Performance & Customs Limited | Wholesale & retail | 2023 |
| Treidliacht Limited | Information & communication | 2014 |
| Trent Art Limited | Wholesale & retail | 2017 |
| Trent Solicitors Ltd | Professional & scientific | 2025 |
| Trent Steel Stockholders Ltd | Construction | 2024 |
| Trentcastle Trading Limited | Extraterritorial | 1983 |
| Trentfield Limited | Construction | 2023 |
| Trentwise Ltd | Real estate | 2025 |
| Tri-Dev Limited | Manufacturing | 1977 |
| Triangle Pizza Limited | Hospitality | 2022 |
| Triangolo Ltd | Hospitality | 2017 |
| Trinity West Ltd | Hospitality | 2012 |
| Triochem Ltd | Wholesale & retail | 2024 |
| Tristan Kelly Ltd | Professional & scientific | 2025 |
| Tristec Ltd | Professional & scientific | 2002 |
| Triumph Staffordshire Limited | Extraterritorial | 2006 |
| Trojan Aggregates Limited | Wholesale & retail | 2017 |
| Trojan Grab Hire Ltd | Construction | 2016 |
| True Obsession Ltd | Wholesale & retail | 2015 |
| Trusted Logistics Partners Ltd | Transport & logistics | 2025 |
| Truuman Supplements Limited | Wholesale & retail | 2025 |
| TSR Vehicle Services Ltd | Wholesale & retail | 2012 |
| Tsrj Property Holdings Ltd | Real estate | 2022 |
| TTG Football Community Limited | Education | 2025 |
| TTM Auto Repairs Ltd | Wholesale & retail | 2026 |
| TTR Garage Services Limited | Wholesale & retail | 2013 |
| Tudor Court (Newcastle) Management Company Ltd | Real estate | 1989 |
| Tumble Trophies Limited | Wholesale & retail | 2020 |
| Tunstall Park Boathouse Limited | Hospitality | 2025 |
| Turf Aeration Services Ltd | Administrative & support | 2023 |
| Turkish Gyunther Ltd | Hospitality | 2024 |
| Turney-Wylde (Construction) Limited | Construction | 1967 |
| Turning Heads Car Body Repairs Limited | Manufacturing | 2008 |
| Turning Heads Valeting Products Limited | Wholesale & retail | 2019 |
| Turnocks Defence Solicitors Limited | Professional & scientific | 2019 |
| TW Facilities Management Limited | Administrative & support | 2021 |
| Twelve Arches Holdings Ltd | Real estate | 2025 |
| Twenty Twenty Eight Ltd | Hospitality | 2026 |
| Twentytwo Studio Ltd | Administrative & support | 2019 |
| Twokiwis Ltd | Wholesale & retail | 2021 |
| Tyne Psychology Limited | Health & social care | 2024 |
| Tyne Rest Ltd | Hospitality | 2026 |
| Tyne Tees EPC Ltd | Professional & scientific | 2022 |
| U.Mir Pharma Ltd | Health & social care | 2010 |
| UB Fast Food Ltd | Hospitality | 2022 |
| Uexcel Solutions Ltd | Information & communication | 2022 |
| Uhpc Limited | Manufacturing | 2014 |
| UK Access Scaffolding Limited | Construction | 2018 |
| UK Fire Door Solutions Limited | Financial services | 2014 |
| UK KOI Imports Ltd | Agriculture & fishing | 2025 |
| UK Overnight Ltd | Wholesale & retail | 2021 |
| UK Positive Behaviour Support Community CIC | Education | 2025 |
| UK Royale County Products Limited | Wholesale & retail | 2017 |
| Ultimate Joinery Solutions Ltd | Construction | 2022 |
| Ultralife UK Ltd | Financial services | 2015 |
| Umbrella Care (Midlands) Holdings Ltd. | Financial services | 2019 |
| Unbeatenground Ltd | Administrative & support | 2026 |
| Under Lyme Tree Care Ltd | Agriculture & fishing | 2016 |
| Underdog Marketing Services Ltd | Professional & scientific | 2026 |
| Underground Leisure Events Ltd | Hospitality | 2025 |
| Underground Leisure Ltd | Hospitality | 2024 |
| Underwood Electrical Limited | Construction | 2008 |
| Unibuy Ltd | Wholesale & retail | 2022 |
| Unicore Tech Ltd | Wholesale & retail | 2017 |
| Unicorn Support Ltd | Health & social care | 2021 |
| Unified Network Connections Ltd | Information & communication | 2025 |
| Union Sports Limited | Arts & recreation | 2013 |
| Unique Healthcare Ltd | Health & social care | 2021 |
| Unique Mechanical Services Ltd | Construction | 2014 |
| Unity Vape Ltd | Wholesale & retail | 2020 |
| Universal Joineries (Newcastle) Limited | Manufacturing | 1928 |
| Universal Websites Ltd | Administrative & support | 2016 |
| Unreal Paintball Ltd | Arts & recreation | 2023 |
| Unshrinkable Ltd | Health & social care | 2023 |
| Upland Manor Care Ltd | Health & social care | 2025 |
| Uplifting Spirits Ltd | Hospitality | 2020 |
| Upputuri Ltd | Health & social care | 2013 |
| Urban Base Consultants Limited | Professional & scientific | 2025 |
| Urban Space Properties Ltd | Financial services | 2019 |
| Urgent Delivery Service Ltd | Transport & logistics | 2024 |
| Usah Newcastle Ltd | Health & social care | 2023 |
| UT Vault Ltd | Wholesale & retail | 2026 |
| Utilities & Civils Solutions Ltd | Professional & scientific | 2014 |
| Utter Rubbish Ltd | Information & communication | 2016 |
| Uwla UK Limited | Financial services | 2021 |
| V & M Property Services Limited | Real estate | 2023 |
| V Force Security Ltd | Administrative & support | 2020 |
| V-Fit Training Limited | Arts & recreation | 2017 |
| Vacucom Limited | Wholesale & retail | 1996 |
| VAK Trade Ltd | Construction | 2024 |
| Valencia Salon Ltd | Other services | 2003 |
| Valentina Ilaria Ltd | Wholesale & retail | 2021 |
| Valkyrie Bar Limited | Hospitality | 2023 |
| Valour Prints Ltd | Information & communication | 2019 |
| Van-Uk Ltd | Wholesale & retail | 2023 |