| THE Mindful Injector Academy Ltd | Health & social care | 2025 |
| THE Mortgage Shop Newtownards Ltd | Financial services | 2020 |
| THE New Quays Portavogie Limited | Hospitality | 2020 |
| THE PAT Eakin Foundation | Health & social care | 2024 |
| THE Pottery Nest Ltd | Arts & recreation | 2025 |
| THE Quirky Camper Booth Ltd | Hospitality | 2020 |
| THE Renewable Heat Association Northern Ireland Limited | Administrative & support | 2017 |
| THE Reward Lounge Ltd | Information & communication | 2026 |
| THE Rosslyn Portal Ltd | Administrative & support | 2017 |
| THE Royal Yachting Association Northern Ireland | Arts & recreation | 2004 |
| THE Seventh Magpie Interiors Ltd | Wholesale & retail | 2024 |
| THE SHE Group Ltd | Professional & scientific | 2017 |
| THE Somme Association | Professional & scientific | 1990 |
| THE Spice Inn Portaferry Ltd | Hospitality | 2026 |
| THE Tivoli Bar Ltd | Hospitality | 2021 |
| THE Winners Club N.I Ltd | Arts & recreation | 2023 |
| THE Wright Press Ltd | Information & communication | 2020 |
| Theng Limited | Professional & scientific | 2023 |
| Thermocon NI Ltd | Construction | 2022 |
| Think Network Ltd | Professional & scientific | 2020 |
| Thomas ORR Limited | Real estate | 1958 |
| Thompson Timber (Comber) Ltd | Wholesale & retail | 2007 |
| Thompsons (Northern Ireland) Limited | Professional & scientific | 2012 |
| Thoughtful High Ltd | Wholesale & retail | 2024 |
| THP Construction Ltd | Construction | 2013 |
| Thrive Physiotherapy and Recovery Clinic Ltd | Health & social care | 2026 |
| Thurlow Gate Management Company Ltd | Real estate | 2015 |
| THV Contracts Limited | Construction | 2022 |
| Tianxinxin Limited | Wholesale & retail | 2025 |
| Tiff's Travel Finds Limited | Administrative & support | 2026 |
| Tiheon Limited | Wholesale & retail | 2025 |
| Tilalhna Limited | Wholesale & retail | 2024 |
| Tile Style Interiors Limited | Wholesale & retail | 2007 |
| Tile World Limited | Wholesale & retail | 2020 |
| Tiles Direct Limited | Wholesale & retail | 2015 |
| Tilt-A-Dor Limited | Manufacturing | 1987 |
| Tina Sdyi Ltd | Wholesale & retail | 2024 |
| Titanic FX Store Ltd | Arts & recreation | 2016 |
| Titanic Squash Ltd | Arts & recreation | 2015 |
| TJS Rentals Ltd | Real estate | 2024 |
| TKZ Engineering Ltd | Manufacturing | 2023 |
| TM Drip Ltd | Wholesale & retail | 2025 |
| TM Sky Limited | Wholesale & retail | 2025 |
| TMR Construction Ltd | Construction | 2022 |
| Toast Promotions Ltd | Wholesale & retail | 2021 |
| Tobar Medical Ltd | Health & social care | 2025 |
| Tobe Lucky One Limited | Wholesale & retail | 2025 |
| Todaye Tech Ltd | Wholesale & retail | 2025 |
| Toki Toys Ltd | Manufacturing | 2022 |
| TOM Griffiths Investments Limited | Financial services | 2026 |
| TOM Hero Limited | Manufacturing | 2023 |
| Tona Enterprises Limited | Health & social care | 1994 |
| Tonmean Limited | Wholesale & retail | 2025 |
| TOO Clean Windows Ltd | Administrative & support | 2022 |
| Tool Monster Ltd | Wholesale & retail | 2020 |
| Top Spot (N.I.) Limited | Wholesale & retail | 2020 |
| Tormagna Ltd | Information & communication | 2019 |
| Torney Investments Limited | Real estate | 2022 |
| Torr Fishing Limited | Agriculture & fishing | 2023 |
| Touch of India Limited | Wholesale & retail | 2026 |
| Toye Vehicle Repairs Ltd | Wholesale & retail | 2026 |
| Tracey FUN Limited | Wholesale & retail | 2025 |
| Trade Finder NI Ltd | Information & communication | 2025 |
| Trading Services LS (NI) Limited | Wholesale & retail | 2025 |
| Transform Painting and Decorating Ltd | Construction | 2022 |
| Trasnagh Limited | Construction | 2022 |
| Travel With Jonny and Will Ltd | Administrative & support | 2025 |
| Treashak Limited | Wholesale & retail | 2025 |
| Treasure Umbrella Ltd | Wholesale & retail | 2024 |
| Trialstar Shows Ltd | Wholesale & retail | 2026 |
| Tristan Chaize Ltd | Wholesale & retail | 2025 |
| Truely Catching Limited | Wholesale & retail | 2024 |
| Truska Ltd | Information & communication | 2005 |
| Tréidlia Limited | Professional & scientific | 2019 |
| TS Properties Ltd | Real estate | 2014 |
| TSZ Wing Trading Ltd | Wholesale & retail | 2024 |
| Tthewott Limited | Wholesale & retail | 2025 |
| Ttonerti Limited | Wholesale & retail | 2025 |
| Tufz TPR Ltd | Wholesale & retail | 2024 |
| TUK TUK Bangor Limited | Hospitality | 2020 |
| Tullycarnet Community Support Services Ltd | Administrative & support | 2002 |
| Tullydale Limited | Professional & scientific | 2012 |
| Tullymally Farms Limited | Agriculture & fishing | 2007 |
| Turner Aviation Services Ltd | Education | 2019 |
| Two Laughing Dogs PTY Ltd | Wholesale & retail | 2025 |
| TY Chanthorn Ltd | Wholesale & retail | 2024 |
| Typemr Limited | Wholesale & retail | 2019 |
| U Hire (NI) Limited | Administrative & support | 2015 |
| UB Kircubbin Limited | Real estate | 2018 |
| Ublesemp Ltd | Professional & scientific | 2021 |
| UK Scent Sport Limited | Administrative & support | 2025 |
| Ulaid Limited | Real estate | 2022 |
| Ulbrich Suzana Ltd | Wholesale & retail | 2023 |
| Ulster Castings Limited | Manufacturing | 1965 |
| Ulster Distilleries Limited | Manufacturing | 2002 |
| Ulster Farm Services Ltd | Administrative & support | 2026 |
| Ulster Flying Club (1961) Limited | Arts & recreation | 1961 |
| Ulster Historical Enterprises Ltd | Extraterritorial | 2006 |
| Ulster Vintage Car Club Limited | Arts & recreation | 1989 |
| Ultimate Cleans Ltd | Administrative & support | 2022 |