| Stone Structures Ltd | Construction | 2019 |
| Storey and SON Gardening Services Ltd | Administrative & support | 2023 |
| Strawberry Commercial Limited | Real estate | 2025 |
| Strawberry Housing Limited | Real estate | 2023 |
| Stuart Cairns Business Consultant Ltd | Financial services | 2016 |
| Stuart Yorston Limited | Wholesale & retail | 2008 |
| Studio Cameron Ltd | Professional & scientific | 2023 |
| Sunderland Parking Services Limited | Transport & logistics | 2022 |
| Suretrade Wholesale Limited | Wholesale & retail | 2025 |
| Swarland Brick Company Limited(The) | Agriculture & fishing | 1937 |
| Swinhoe Developments Ltd | Hospitality | 2025 |
| Swinhoe Industries Limited | Information & communication | 2018 |
| Sycamore Synapse Consultants Limited | Information & communication | 2025 |
| Synergy Sustainability Consultants Limited | Professional & scientific | 2005 |
| T618 Capital Ltd | Financial services | 2026 |
| Target Training Associates Limited | Professional & scientific | 2002 |
| Target Training Digital Gateway Limited | Education | 2023 |
| Tate & Bell Ltd | Hospitality | 2025 |
| Teasdale Properties (NE) Limited | Construction | 2022 |
| Terabithia Pictures Ltd | Information & communication | 2021 |
| THE Advent Hope Limited | Real estate | 2026 |
| THE ALN Valley Railway Trust | Transport & logistics | 1997 |
| THE Alnwick Bakery Ltd | Manufacturing | 2022 |
| THE Alnwick Brewery Company Limited | Manufacturing | 2005 |
| THE Alnwick Cryer Limited | Information & communication | 2014 |
| THE Alnwick Gallery Ltd | Wholesale & retail | 2024 |
| THE Alnwick Garden Trust | Administrative & support | 2002 |
| THE Alnwick RUM and Spirits Company Limited | Manufacturing | 2003 |
| THE Bailiffgate Museum and Gallery | Arts & recreation | 2008 |
| THE Big House Investments Limited | Real estate | 2024 |
| THE Birdcage (Alnwick) Limited | Hospitality | 2025 |
| THE Burgage Holders of Alnmouth Common Limited | Hospitality | 2008 |
| THE Butterchurn B&B Ltd | Hospitality | 2023 |
| THE Callaly Estates Company Limited | Agriculture & fishing | 1940 |
| THE Chimney Doctor Northumberland Ltd | Construction | 2019 |
| THE Coffee Box by Chatton Village Store Ltd | Manufacturing | 2021 |
| THE Doxford Group (Management) Ltd | Professional & scientific | 2021 |
| THE Eslington Sustainable Energy Company Limited | Energy | 2009 |
| THE Fishing Boat Inn Accommodation Ltd | Hospitality | 2026 |
| THE Fishing Boat Inn Limited | Hospitality | 2021 |
| THE Georgian House Alnwick Ltd | Hospitality | 2018 |
| THE Good Life Shop (Wooler) Ltd | Hospitality | 2025 |
| THE Highlander Belsay Ltd | Hospitality | 2022 |
| THE Holy Island Brewery Limited | Extraterritorial | 2019 |
| THE Horseshoes Inn, Rennington Limited | Hospitality | 2024 |
| THE House Sommelier Ltd | Arts & recreation | 2026 |
| THE ID Band Company Limited | Other services | 2010 |
| THE Kitchenware Company (NE) Limited | Manufacturing | 2015 |
| THE Lindisfarne Brewery Limited | Extraterritorial | 2019 |
| THE Mews Furnishings Limited | Wholesale & retail | 2018 |
| THE North Northumberland Hospice | Health & social care | 2003 |
| THE Northumbrian Anglers Federation Limited | Agriculture & fishing | 2022 |
| THE Northumbrian Artisan Pizza Company Ltd | Hospitality | 2023 |
| THE OAT Kitchen Ltd | Manufacturing | 2021 |
| THE Occupational Therapy Service Limited | Extraterritorial | 2025 |
| THE Old Fenwick Village Hall Limited | Wholesale & retail | 2019 |
| THE Old Road Ltd | Hospitality | 2026 |
| THE OT Service Limited | Health & social care | 2014 |
| THE Poppy Archive Ltd | Wholesale & retail | 2026 |
| THE Real Taste of Northumberland Ltd | Hospitality | 2016 |
| THE Ship Ashore Limited | Hospitality | 2024 |
| THE Ship Inn & Brewery Ltd | Hospitality | 2015 |
| THE Training Cabin Ltd | Education | 2019 |
| THE Trimodular Group Limited | Professional & scientific | 2024 |
| THE Village Inn PUB Company Ltd | Extraterritorial | 2011 |
| THE Wellfield Apartment Management Company Ltd | Households | 2009 |
| THE Wellfield Gardens Management Company Ltd | Households | 2009 |
| Thew Consulting Limited | Professional & scientific | 2026 |
| Thistle Property Developments Ltd. | Real estate | 2011 |
| Thompson Opticians Limited | Wholesale & retail | 1987 |
| Thorndyke Park Ltd | Hospitality | 2025 |
| Thornton Contracting Ltd | Construction | 2014 |
| Three Suns PUB Ltd | Hospitality | 2022 |
| Thrunton Woods Holiday Park Limited | Real estate | 2016 |
| Thunder Road Properties Ltd | Real estate | 2016 |
| Time to Care Specialist Support Services Limited | Real estate | 2013 |
| TJE Properties Ltd | Real estate | 2025 |
| TMG Forecourts Ltd | Wholesale & retail | 2024 |
| TOM White (Media) Ltd | Information & communication | 2011 |
| Top & Co. Property Limited | Real estate | 2020 |
| Topspot Services (Leeming) Limited | Wholesale & retail | 2008 |
| Topspot Services (Marske) Limited | Wholesale & retail | 2008 |
| Topspot Services Ltd | Wholesale & retail | 2004 |
| Torch Technical Services Ltd | Professional & scientific | 2023 |
| Touchstone Science Ltd | Manufacturing | 2015 |
| Tourism Fair Limited | Administrative & support | 2023 |
| Trading Enterprises Albury Limited | Hospitality | 1987 |
| Trail Finder Coaching Ltd | Health & social care | 2023 |
| Treadforce of Alnwick Ltd | Wholesale & retail | 2023 |
| Treetops East Management Company Limited | Households | 2019 |
| Treliganus Limited | Construction | 1979 |
| Tridenta Associates Ltd | Professional & scientific | 2010 |
| TRU Alnwick Limited | Real estate | 2016 |
| TRU Physiotherapy Limited | Health & social care | 2012 |
| TRU Yoga Limited | Arts & recreation | 2016 |
| True North Real Asset Partners Limited | Construction | 2004 |
| Truman Homes Limited | Construction | 2002 |
| Tughall Grange Farm Limited | Agriculture & fishing | 2009 |
| Turnbull's Northumbrian Foodhall Ltd | Wholesale & retail | 2019 |
| Tynemouth Holdco Limited | Financial services | 2025 |