| Tattymoyle Farm Ltd | Agriculture & fishing | 2019 |
| TBS Embroidery Ltd | Wholesale & retail | 2025 |
| TCA Management Ltd | Households | 2020 |
| Tcautostore Limited | Wholesale & retail | 2017 |
| Telco Trading Limited | Arts & recreation | 1984 |
| Termaur Limited | Financial services | 2020 |
| Termon Farm Supplies Ltd | Wholesale & retail | 2005 |
| Termon Fuels Ltd | Administrative & support | 2010 |
| Termon Plant Limited | Construction | 2019 |
| Terracotta Coffee Ltd | Hospitality | 2024 |
| Terramach Imports Ltd | Wholesale & retail | 2025 |
| Tesab Engineering Limited | Manufacturing | 1992 |
| TG Groundworks Limited | Construction | 2014 |
| TGM Tools Ltd | Wholesale & retail | 2025 |
| Thal Farms Ltd | Agriculture & fishing | 2025 |
| THE Athletic Performance Platform Ltd | Arts & recreation | 2025 |
| THE Auld Forge Ltd | Wholesale & retail | 2022 |
| THE Best Water N.I. Ltd | Wholesale & retail | 2025 |
| THE Bizzi Company Ltd | Wholesale & retail | 2013 |
| THE Blind Cobbler Limited | Hospitality | 2016 |
| THE Business Partnership (NI) Ltd | Professional & scientific | 2012 |
| THE Central Bar Dromore Ltd | Hospitality | 2024 |
| THE Coach Inn (Omagh) Ltd | Hospitality | 2018 |
| THE Copper TAP Group Ltd | Hospitality | 2020 |
| THE Cowshed Vintage Ltd | Other services | 2020 |
| THE Creative Media Company (NI) Limited | Professional & scientific | 1999 |
| THE Diamonds Holding Company Limited | Financial services | 2019 |
| THE Fharmacy Ltd | Other services | 2019 |
| THE Firs Services (Ireland) Limited | Health & social care | 2014 |
| THE Flourworks Coffee Co. Ltd | Hospitality | 2015 |
| THE Flourworks Ltd | Hospitality | 2015 |
| THE Fraud Company Limited | Administrative & support | 2009 |
| THE Glebe Bar Limited | Hospitality | 2016 |
| THE Goldmine Jewellers (Omagh) Ltd | Wholesale & retail | 2017 |
| THE Kitchen Omagh Limited | Hospitality | 2017 |
| THE Mellon Country Inn Ltd | Hospitality | 2017 |
| THE Millstone Omagh Limited | Hospitality | 2018 |
| THE Spa Alchemists Ltd | Wholesale & retail | 2019 |
| THE Spectacle Maker Omagh Ltd | Wholesale & retail | 2015 |
| THE Strule Hotel Ltd | Hospitality | 2024 |
| THE Three Sisters (N.I.) Ltd | Hospitality | 2020 |
| THE Whistler's Kitchen Ltd | Hospitality | 2023 |
| Thermowall Limited | Construction | 2020 |
| Thirsty Doodle Limited | Administrative & support | 2021 |
| Thompson Electrical Contractors Ltd | Construction | 2023 |
| Thorn Bio-Scientific Limited | Professional & scientific | 2011 |
| Thornaglog Energy Limited | Energy | 2016 |
| Three Sisters Food Limited | Hospitality | 2026 |
| TIC Poultry Limited | Agriculture & fishing | 2011 |
| Ticarl Ltd | Water & waste | 2020 |
| Tierney & SON Painting & Decorating Ltd | Construction | 2021 |
| Tirooney Building Solutions Ltd | Construction | 2026 |
| Tiroony Eggs Limited | Agriculture & fishing | 2017 |
| Tirquin Distribution Ltd | Wholesale & retail | 2012 |
| Titan Plant and Commercial Sales Ltd | Manufacturing | 2021 |
| Tivockmoy Farm Limited | Agriculture & fishing | 2018 |
| TK MAC Ltd | Professional & scientific | 2024 |
| TMD Construction Building Ltd | Construction | 2025 |
| TOH Contracts Ltd | Construction | 2015 |
| Tolan Bros Ltd | Manufacturing | 2015 |
| Tona Construction Ltd | Construction | 2011 |
| Tonaghamore Ltd | Real estate | 2025 |
| Tonene Contracts Ltd | Construction | 2019 |
| Tonene Properties Ltd | Real estate | 2024 |
| Tonnagh Contracts Ltd | Construction | 2026 |
| Tonnaghmore Energy Ltd | Energy | 2013 |
| Toolbox.Net Limited | Wholesale & retail | 2001 |
| Tools Galore Ltd | Wholesale & retail | 2020 |
| Top Gear Competitions Limited | Wholesale & retail | 2024 |
| Top Gear Motors Car and Commercials Ltd | Wholesale & retail | 2014 |
| Top of the Mountain Ltd | Extraterritorial | 2024 |
| Torrent Valley Foods Ltd | Hospitality | 2025 |
| Toshe Trading Limited | Transport & logistics | 1986 |
| Total PAY Services Ltd | Professional & scientific | 2025 |
| Total Pipe Fabrications Limited | Construction | 2023 |
| Tradie Management Ltd | Administrative & support | 2026 |
| Transko Haulage Ltd | Transport & logistics | 2018 |
| Transko Ltd | Transport & logistics | 2018 |
| Tremoge Developments Ltd | Construction | 2017 |
| Trevor Cathers Ltd | Transport & logistics | 2015 |
| Trigon Fitness Ltd | Wholesale & retail | 2021 |
| Trillick Autopart Centre Ltd | Wholesale & retail | 2011 |
| Trillick Civil Engineering Ltd | Construction | 2019 |
| Trillick Enterprises Limited | Real estate | 1994 |
| Trillick Tractors Ltd | Wholesale & retail | 2012 |
| Triple Arch Holdings Limited | Financial services | 2014 |
| Trompets Ltd | Hospitality | 2023 |
| Trustie Technology Limited | Information & communication | 2018 |
| TSC Properties Ltd | Real estate | 2024 |
| TSC Property Management Ltd | Households | 2025 |
| TT Thermal Insulation and Fire Protection Limited | Construction | 2002 |
| Tullycorker Poultry Ltd | Agriculture & fishing | 2024 |
| Tullyneil Farms Limited | Agriculture & fishing | 2022 |
| Tullyrush Investments Limited | Construction | 2021 |
| Tune UP Omagh CIC | Agriculture & fishing | 2023 |
| Turbett & Co Ltd | Professional & scientific | 2006 |
| TW Gym Limited | Other services | 2020 |
| Tycork Properties Ltd | Real estate | 2020 |
| Tyrcon Construction Ltd | Construction | 2026 |
| Tyre & Wheel Limited | Wholesale & retail | 2019 |