| THE Radiator Shed Limited | Wholesale & retail | 2020 |
| THE Ralphs Group Ltd | Other services | 2018 |
| THE Reform LAB Gateshead Ltd | Arts & recreation | 2025 |
| THE Rickshaw Room Ltd | Hospitality | 2026 |
| THE Riverside Pantry Limited | Hospitality | 2021 |
| THE Schooner Gateshead Ltd | Hospitality | 2019 |
| THE Skill Mill Limited | Administrative & support | 2013 |
| THE Skill Mill Newcastle Community Interest Company | Extraterritorial | 2013 |
| THE Skintelligent Chic Ltd | Other services | 2025 |
| THE Smile Yard Ltd | Health & social care | 2021 |
| THE Southern Amusements & General Trading Company (1945) | Extraterritorial | 1945 |
| THE Staiths Group Limited | Hospitality | 2022 |
| THE Standing CT Company Limited | Health & social care | 2016 |
| THE Technicolour Project Ltd | Administrative & support | 2023 |
| THE Third I Studio Limited | Professional & scientific | 2024 |
| THE Treatment Rooms LOW Fell Ltd | Other services | 2025 |
| THE Tree Surveying Company Limited | Professional & scientific | 2018 |
| THE TV Agency Limited | Professional & scientific | 2011 |
| THE View Tynemouth Limited | Hospitality | 2024 |
| THE Warhurst and Bourne Partnership Limited | Professional & scientific | 2014 |
| THE Welfare Dwellings Trust Limited | Real estate | 1989 |
| THE Wellness Hub Heaton Ltd | Arts & recreation | 2024 |
| THE Wellness Hub Newcastle Ltd | Arts & recreation | 2020 |
| THE Westgrove Lane Freehold Company Limited | Real estate | 2011 |
| THE Whole Sch-Bang Event Decor Ltd | Other services | 2022 |
| THE Willows School Limited | Education | 2024 |
| THE Window Outlet Workington Limited | Other services | 2005 |
| THE Work Place Ltd | Real estate | 2025 |
| THE Workcast Corporation Limited | Information & communication | 2008 |
| THE Worthy WAX Company Limited | Wholesale & retail | 2021 |
| Theamani Holdings Limited | Financial services | 2026 |
| Thefidlertreecompany Limited | Real estate | 2025 |
| Thekitchen@Sutherlands Ltd | Hospitality | 2025 |
| Thenovalink Innovation Ltd | Wholesale & retail | 2025 |
| Theo Construction Utilities Ltd | Construction | 2022 |
| Thermal Properties Ltd | Real estate | 2022 |
| Thermodynamix (Holdings) Limited | Professional & scientific | 2004 |
| Thermodynamix Thermoforming Specialist Services Limited | Manufacturing | 1999 |
| Thesisiq Ltd | Information & communication | 2026 |
| THF Bottles Limited | Extraterritorial | 2018 |
| THF Digital Limited | Extraterritorial | 2021 |
| THF Glassware Limited | Extraterritorial | 2021 |
| THF Holdings Ltd | Financial services | 2014 |
| THF Homes Limited | Real estate | 2021 |
| Thinking Digital Limited | Administrative & support | 2012 |
| Third Space Events LLP | | 2017 |
| Thirlwell Forestry Limited | Agriculture & fishing | 2011 |
| Thirteen Insights Ltd | Professional & scientific | 2026 |
| Thoburns Enforcement Services Limited | Administrative & support | 1990 |
| Thomason & White Limited | Hospitality | 2024 |
| Thompkins and Thompkins Facilities Management Limited | Professional & scientific | 1989 |
| Thompson Convenience Store (Guidepost) Ltd | Wholesale & retail | 2017 |
| Thompson Convenience Stores (Cramlington) Ltd | Wholesale & retail | 2010 |
| Thompson Convenience Stores (Denton) Ltd | Wholesale & retail | 2012 |
| Thompson Convenience Stores (Dewley) Ltd | Wholesale & retail | 2012 |
| Thompson Convenience Stores (Gosforth) Ltd | Wholesale & retail | 2012 |
| Thompson Convenience Stores (Guidepost) LLP | | 2014 |
| Thompson Convenience Stores (Holdings) Limited | Financial services | 2012 |
| Thompson Convenience Stores (Sandyford) Ltd | Wholesale & retail | 2012 |
| Thompson Convenience Stores (Springwell) Ltd | Wholesale & retail | 2012 |
| Thompson Convenience Stores (Walbottle) Ltd | Wholesale & retail | 2012 |
| Thompson Facilities and Project Management Services Ltd | Administrative & support | 2015 |
| Thornley Properties Limited | Real estate | 1986 |
| Three Stars Financial Solutions (UK) Limited | Financial services | 2024 |
| Three Tuns Sheriffs Highway Limited | Extraterritorial | 2014 |
| Thrift Energy Group Limited | Financial services | 2019 |
| Thrift Energy Limited | Construction | 2012 |
| Thrift Financial Limited | Professional & scientific | 2014 |
| Through the Trees CIC | Health & social care | 2023 |
| Thrower Stone Group Ltd | Construction | 2022 |
| Thrower Stone Investments Limited | Real estate | 2005 |
| Thrower Stone Ltd | Real estate | 2004 |
| Thrower Stone PM Ltd | Administrative & support | 2022 |
| Thrower Stone Property Management Ltd | Real estate | 2007 |
| Thule Trading Limited | Hospitality | 2013 |
| Thursby Homes (Springs) Limited | Construction | 2018 |
| Thursby Homes Limited | Real estate | 2016 |
| Tida Energy Harvesting Ltd | Professional & scientific | 2023 |
| Tideway & Marine Consulting Ltd | Professional & scientific | 2023 |
| Tiger Facility Solutions Ltd | Administrative & support | 2020 |
| Till I DIE Ltd | Wholesale & retail | 2023 |
| TIME2TRAIN Ltd | Education | 2013 |
| Timec 1526 Limited | Extraterritorial | 2015 |
| Timec 1623 Limited | Real estate | 2017 |
| Timeless Charger Ltd | Wholesale & retail | 2018 |
| Timshel Holdings Limited | Wholesale & retail | 2009 |
| Tint Consultancy Services Ltd | Health & social care | 2022 |
| Tiny Eco Homes UK Limited | Manufacturing | 2017 |
| Tips Football Consultancy Services Limited | Professional & scientific | 2024 |
| Tiptop Food Ltd | Hospitality | 2024 |
| Titan Mechanical Ltd | Manufacturing | 2026 |
| Titan Property (Newcastle) Limited | Other services | 2004 |
| Titanis Holdings Ltd | Construction | 2025 |
| Titanvolt Industries Limited | Financial services | 2024 |
| Titanvolt Limited | Wholesale & retail | 2024 |
| TJ Global Network Ltd | Wholesale & retail | 2025 |
| TK Thompson Ltd | Professional & scientific | 2007 |
| Tkmti Collections Ltd | Wholesale & retail | 2024 |
| TKO Boxing & Fitness Centre Ltd | Education | 2020 |
| TLG Joinery Solutions Limited | Construction | 2026 |