| Theautopilot Ltd | Wholesale & retail | 2024 |
| Thebarrington Limited | Hospitality | 2025 |
| Thermacourse Ltd | Professional & scientific | 2025 |
| Thermashield Passive Fire Ltd | Construction | 2025 |
| Think Like a Pilot Ltd | Professional & scientific | 2020 |
| Thirlwell Cleaning Ltd | Administrative & support | 2025 |
| Thirteen (Whitley Bay) Ltd | Hospitality | 2023 |
| Thompson Roofing and Lead Specialists Ltd | Construction | 2017 |
| Thornleigh House Management Limited | Households | 1984 |
| Three Tanners Limited | Hospitality | 2020 |
| Thunderoar Ltd | Arts & recreation | 2005 |
| Tiger Spice Pizzeria Ltd | Hospitality | 2025 |
| Timbs and Ford Ltd | Financial services | 2019 |
| Time and Tide Tattoos Ltd | Other services | 2015 |
| Tinbum Tuning Ltd | Manufacturing | 2019 |
| Tine Engineering & Design Ltd | Professional & scientific | 2019 |
| Tint My Ride Limited | Other services | 2005 |
| Tiny Cactus Ltd | Information & communication | 2016 |
| Tipsforfilming Ltd | Professional & scientific | 2022 |
| TJK Sangha Limited | Wholesale & retail | 2022 |
| TMD Properties and Developments Limited | Real estate | 2021 |
| TMG the Marketing Guys Limited | Professional & scientific | 2018 |
| TMS Installations Limited | Construction | 2025 |
| Tommy BOO Ltd | Other services | 2014 |
| Tony Cook Lighting for Film & Television Limited | Information & communication | 2009 |
| Tony Foster Hair Ltd | Other services | 2026 |
| Topher Mcgrillis Photography Ltd | Professional & scientific | 2011 |
| Toucan DO IT Ltd | Real estate | 2023 |
| Towco Limited | Extraterritorial | 2011 |
| Tower Maintenance Limited | Construction | 1994 |
| Towsu Ltd | Information & communication | 2023 |
| TP Fitness Gym and Personal Training Ltd | Arts & recreation | 2019 |
| TP Tech Inspection Ltd | Professional & scientific | 2017 |
| Tracy Tolan Occupational Health Services Ltd | Health & social care | 2010 |
| Trading Places Ponteland Limited | Real estate | 2007 |
| Tramp Innovations Ltd | Information & communication | 2013 |
| Treebay Ltd | Households | 2011 |
| Treehorn Offshore Ltd | Professional & scientific | 2022 |
| Trends TV Ltd | Information & communication | 2024 |
| Treyarnon Technology Solutions Limited | Information & communication | 2013 |
| Tribe Tesi Ltd | Administrative & support | 2023 |
| Tricky Limited | Administrative & support | 2003 |
| Tridentuk Ltd | Wholesale & retail | 2002 |
| Trimtab Services Limited | Professional & scientific | 2021 |
| Tripfox Ltd | Administrative & support | 2025 |
| Tripura Developments Ltd | Construction | 2025 |
| True North Engineering Supplies Ltd | Wholesale & retail | 2025 |
| True North Surf C.I.C. | Arts & recreation | 2024 |
| TSD Plastering Ltd | Construction | 2025 |
| Turbo-Rs Limited | Wholesale & retail | 2024 |
| Turbytown Ltd | Information & communication | 2026 |
| Turkish Delight Whitley Ltd | Hospitality | 2019 |
| Turknaz Limited | Wholesale & retail | 2016 |
| Turney Tiles Limited | Wholesale & retail | 2021 |
| Turnkey Consultancy Limited | Professional & scientific | 2023 |
| Twinid Solutions Ltd | Information & communication | 2024 |
| Twinova Consulting Ltd | Information & communication | 2024 |
| Twisted Cabling Limited | Construction | 2015 |
| Two by Two Brewing Ltd | Manufacturing | 2013 |
| Two by Two TAP Limited | Hospitality | 2022 |
| Two Rivers Holdco Limited | Financial services | 2018 |
| TWS 79 Ltd | Wholesale & retail | 2021 |
| Tyde Sea View Sauna Ltd | Other services | 2025 |
| Tyne & Tweed Estates Ltd | Real estate | 2018 |
| Tyne & Wear Scaffolding Limited | Construction | 1999 |
| Tyne and Wire Electrical Solutions Limited | Construction | 2019 |
| Tyne Attire UK Ltd | Wholesale & retail | 2024 |
| Tyne Bay Limited | Hospitality | 2022 |
| Tyne Tees Ceramics (Sunderland) Limited | Wholesale & retail | 2016 |
| Tynemouth IP Limited | Professional & scientific | 2026 |
| Tyneside Engineering Limited | Professional & scientific | 2025 |
| Tyneside Gymnastics Club Ltd | Arts & recreation | 2013 |
| Tyneside Lasers Ltd | Manufacturing | 2019 |
| Tyneside Mortgage Advice Centre Limited | Financial services | 2002 |
| Tyneside Powder Coatings Ltd | Manufacturing | 2019 |
| Tyneside Site Investigations Ltd | Professional & scientific | 2012 |
| Uarc Ltd | Education | 2022 |
| UK Better Bargains Ltd | Wholesale & retail | 2024 |
| UK Palliative Care Collaborative (Ukpcc) C.I.C. | Other services | 2025 |
| Umodow Ltd | Wholesale & retail | 2021 |
| Uncle's RS Ltd | Hospitality | 2026 |
| Under One Roof Collective Ltd | Wholesale & retail | 2024 |
| Underbreeze Ltd | Professional & scientific | 2008 |
| Underdog Tattooing Balm Limited | Wholesale & retail | 2022 |
| Underwaterthing Ltd | Arts & recreation | 2026 |
| Unique Boutique (NE) Ltd | Wholesale & retail | 2013 |
| Unisteps Recruit UK Ltd | Professional & scientific | 2025 |
| United Heating & Plumbing Ltd | Construction | 2019 |
| Unity Platform Ltd | Information & communication | 2025 |
| Universal Painting & Decorating Ltd | Construction | 2023 |
| UP a Height Limited | Extraterritorial | 2014 |
| UP Line Training Limited | Education | 2016 |
| Upfront Properties Limited | Households | 2020 |
| Upnorth Building Company Ltd | Construction | 2022 |
| Upsilondm Limited | Professional & scientific | 2010 |
| URF Limited | Professional & scientific | 2009 |
| Usher Barr Architects Ltd | Professional & scientific | 2021 |
| Valley Accountancy Ltd | Professional & scientific | 2018 |
| Valley Falcons Limited | Agriculture & fishing | 2023 |
| Valvori Limited | Real estate | 2022 |