| THE UK Utility Guys Ltd | Administrative & support | 2026 |
| THE Westwoods Property Management Limited | Real estate | 2011 |
| Therossharkness Ltd | Information & communication | 2022 |
| Thomas Hutchinson and Sons Limited | Manufacturing | 1956 |
| Thomas Mcdonald Ltd | Other services | 2024 |
| Tickety Marketing Ltd | Information & communication | 2013 |
| TIG 006 Limited | Wholesale & retail | 2010 |
| Tillburn Limited | Extraterritorial | 2011 |
| TIME2 Media Communications Ltd | Information & communication | 2013 |
| Tiny Tots Pre-School Education Centre | Other services | 2010 |
| TIR Contract Services Limited | Construction | 2023 |
| Titanic Suites Belfast Ltd | Real estate | 2012 |
| Titanicmechanics Ltd | Wholesale & retail | 2022 |
| TNG Contracts Ltd | Construction | 2025 |
| Tobin Centre (Moortown) Ltd | Arts & recreation | 2012 |
| Tobin Drive Management Company Ltd | Households | 2020 |
| Tobin Limited | Hospitality | 1989 |
| Together Fitness Clonoe Ltd | Arts & recreation | 2026 |
| Top Foods Limited | Wholesale & retail | 2006 |
| Torelli (NI) Ltd | Water & waste | 2008 |
| Toro Homes Ltd | Manufacturing | 2014 |
| Town Lets Ltd | Construction | 2015 |
| TR Analysis Ltd | Information & communication | 2017 |
| Trade Mouldings Distribution Limited | Wholesale & retail | 2002 |
| Trade Mouldings Holdings Limited | Financial services | 2023 |
| Trade Mouldings Limited | Manufacturing | 1982 |
| Trainor-Watt Properties Limited | Real estate | 2022 |
| Transfare Ltd | Information & communication | 2018 |
| Triphane Limited | Financial services | 2020 |
| Trja Property Developers Ltd | Real estate | 2024 |
| Tullagh Holdings Ltd | Financial services | 2018 |
| Tullagh Investments Ltd | Financial services | 2022 |
| Tullycoose Ltd | Construction | 2010 |
| Tullynure Construction Ltd | Construction | 2012 |
| Turbo Leisure Limited | Wholesale & retail | 1999 |
| Turco Engineering Limited | Manufacturing | 2001 |
| Turkington Construction Ltd | Construction | 2000 |
| Tyrone Crafted Glass CIC | Manufacturing | 2021 |
| UA Neill Industries Ltd | Manufacturing | 2023 |
| Ulster Concrete Plant Ltd | Administrative & support | 2025 |
| Ulster Concrete Pumping Ltd | Construction | 2025 |
| Union ST Ltd | Professional & scientific | 2016 |
| Univit Ltd | Manufacturing | 2004 |
| Used Screens & Crushers Worldwide Ltd | Wholesale & retail | 2005 |
| V Fraser & Sons Ltd | Transport & logistics | 2002 |
| V K Removals and Storage Ltd | Transport & logistics | 2012 |
| Validaid Ltd | Information & communication | 2019 |
| Vantoru Ltd | Information & communication | 2024 |
| Vaporo Solutions Ltd | Wholesale & retail | 2019 |
| Vehicle Tracker NI Ltd | Wholesale & retail | 2025 |
| VES Solutions Ltd | Energy | 2024 |
| Victoria Camera and Video Centre Limited | Wholesale & retail | 1983 |
| Village Depot Ltd | Wholesale & retail | 2016 |
| Viper Precision Engineering Ltd | Professional & scientific | 2019 |
| Viva Tech Talent Ltd | Administrative & support | 2025 |
| Vizi Transport Solution Ltd | Transport & logistics | 2025 |
| VK Storage NI Ltd | Wholesale & retail | 2016 |
| Vwab NI Ltd | Water & waste | 2024 |
| W.D. & M.C. Alexander Construction Limited | Energy | 1989 |
| Wall Effects Limited | Construction | 2003 |
| Walnut Drive Company Limited | Real estate | 2021 |
| Waterberg Properties Limited | Construction | 2005 |
| Wave (NI) Ltd | Wholesale & retail | 1998 |
| Wave the Animals Ltd | Wholesale & retail | 2021 |
| WCG Events Ltd | Arts & recreation | 2019 |
| WE Charge Your Car Limited | Wholesale & retail | 2021 |
| Weddings by Nightowl Ltd | Professional & scientific | 2024 |
| WEE Adventurers Ltd | Hospitality | 2023 |
| Wellwood Adami Ltd. | Construction | 2007 |
| West-Fire Ltd | Construction | 2024 |
| Westland Developments (NI) Limited | Construction | 2003 |
| Westwoods Services Ltd | Other services | 2024 |
| Westyu Limited | Wholesale & retail | 2024 |
| WGC Youth Events Ltd | Arts & recreation | 2024 |
| White Lily Bay Company Limited | Professional & scientific | 2025 |
| Whitefield Properties Limited | Real estate | 2007 |
| Whoopsie DOT COM Limited | Wholesale & retail | 2025 |
| Wild Geese Parachute Ltd | Arts & recreation | 2016 |
| Wilkinson Fitness Ltd | Arts & recreation | 2017 |
| Wizard of Dogs Training School Ltd | Education | 2024 |
| Wonders of Wellbeing Limited | Other services | 2021 |
| Woodhill Holdings Ltd | Financial services | 2017 |
| Woodvale Tree Properties Limited | Real estate | 2023 |
| Xazfriends Ltd | Hospitality | 2025 |
| XCAV8 Plant & Machinery Ltd | Wholesale & retail | 2019 |
| Xtraspace Self Storage Ltd | Transport & logistics | 2019 |
| YAU Cookstown Ltd | Hospitality | 2015 |
| Zoltan Solution Limited | Financial services | 2024 |