| THE Rocks Luxury Accommodation Ltd | Hospitality | 2025 |
| THE Safety Elephant Ltd | Other services | 2022 |
| THE Sales Bureau Ltd | Extraterritorial | 2013 |
| THE Sales Practice Ireland Ltd | Professional & scientific | 2013 |
| THE Secret Host Ltd | Hospitality | 2024 |
| THE Sound Mind Collective Ltd | Information & communication | 2025 |
| THE Spires Portadown Management Ltd | Households | 2020 |
| THE Strain Practice Ltd | Financial services | 2020 |
| THE Student Gift Box UK Ltd | Wholesale & retail | 2025 |
| THE Tax Cafe (TTC) Ltd | Professional & scientific | 2020 |
| THE Tyre & Auto Centre Ltd | Wholesale & retail | 2012 |
| THE Tyre Outlet (NI) Limited | Wholesale & retail | 2015 |
| THE Vallen Group Limited | Real estate | 2016 |
| THE WEE Gardening & Pressure Washing Service Ltd | Administrative & support | 2024 |
| THE Welcome Inn Ltd | Hospitality | 2015 |
| THE Well Studios Ltd | Other services | 2026 |
| THE Well Support Hub CIC | Health & social care | 2025 |
| THE White Gallery Ireland Ltd | Wholesale & retail | 2016 |
| THE White House Furniture Ltd | Wholesale & retail | 2017 |
| THE Wild Boar Trading Company Limited | Administrative & support | 2013 |
| THE Wild Rose Boutique Newry Ltd | Wholesale & retail | 2016 |
| THE Wood Floor Shop (NI) Ltd | Manufacturing | 2012 |
| THE Write Magpie Limited | Information & communication | 2015 |
| THE Yellow Heifer Limited | Hospitality | 2008 |
| Thebatteryshop Ltd | Manufacturing | 2021 |
| Thee Cottage Beauty Limited | Other services | 2023 |
| Thee County Carpets & Furniture Store Ltd | Extraterritorial | 2003 |
| Thegymlurgan Ltd | Arts & recreation | 2026 |
| Theia Trading Ltd | Wholesale & retail | 2023 |
| Theitfolder Ltd | Extraterritorial | 2015 |
| Therese Florists Ltd | Wholesale & retail | 2021 |
| Thermahood Ltd | Manufacturing | 2013 |
| Therockrevival Ltd | Information & communication | 2024 |
| Theta Actuarial Limited | Professional & scientific | 2018 |
| Think Coffee (NI) Limited | Hospitality | 2010 |
| Think Projects Managed UK Ltd | Professional & scientific | 2025 |
| Think Safe Ltd | Wholesale & retail | 2025 |
| Third Frontier Labs Limited | Professional & scientific | 2024 |
| Third Sector Connect Ltd | Professional & scientific | 2020 |
| THJ Group Holdings Ltd | Financial services | 2022 |
| Thomas Davis Development Company | Arts & recreation | 2015 |
| Thomas Keenan Ltd | Construction | 2025 |
| Threadmark Newry Limited | Wholesale & retail | 2010 |
| Thredmark Ireland Ltd | Wholesale & retail | 2023 |
| Three Mile Media Limited | Wholesale & retail | 2026 |
| Three One Solar Ltd | Construction | 2022 |
| Three Square Properties Ltd | Households | 2018 |
| Thrifty Bull Finance Ltd | Professional & scientific | 2020 |
| Tichburn Ltd | Extraterritorial | 2012 |
| Tiddly Town Newry Ltd | Hospitality | 2022 |
| Tier One Engineering Solutions Ltd | Manufacturing | 2025 |
| Tiernans Solicitors (Newry) Limited | Professional & scientific | 2014 |
| Tievecrom Fuels Limited | Wholesale & retail | 2011 |
| Tievecrom Ltd | Wholesale & retail | 2022 |
| Tilco Trading PTE Ltd | Wholesale & retail | 2025 |
| Timber & Tile Properties Limited | Real estate | 2008 |
| Timber & Tile Trade Limited | Wholesale & retail | 2008 |
| Timbermark Manufacture Limited | Manufacturing | 2011 |
| Timbervale Property Services Limited | Real estate | 1991 |
| Timeless Stitches Ltd | Manufacturing | 2025 |
| Timeline (N.I.) Ltd | Health & social care | 2014 |
| Timett Limited | Wholesale & retail | 2019 |
| Tinley Tandoori Ltd | Hospitality | 2018 |
| Tinnelly (Demolition) Limited | Construction | 1982 |
| Tinnelly Consultancy Ltd | Professional & scientific | 2025 |
| Tinnelly Environmental Ltd | Extraterritorial | 2003 |
| Tinnelly European Ltd | Transport & logistics | 2021 |
| Tinnelly Group Limited | Financial services | 2017 |
| Tinnelly Holdings Limited | Financial services | 2020 |
| Tinnelly Indian Cuisine Ltd | Hospitality | 2025 |
| Tinnelly Recycling Ltd | Extraterritorial | 2003 |
| Tint NI Limited | Manufacturing | 2025 |
| TIR NA NOG Hair and Beauty Products Limited | Other services | 2015 |
| Tirkelly Limited | Financial services | 2025 |
| Titan Sportz Limited | Wholesale & retail | 2024 |
| Titanic AI Solutions Ltd | Information & communication | 2024 |
| TK Bricklaying Ltd | Construction | 2025 |
| TK Road Services NI Ltd | Transport & logistics | 2025 |
| TL Timbercraft Limited | Manufacturing | 2023 |
| TLC Kitchens and Bedrooms Limited | Manufacturing | 2018 |
| TLC Stonemasonry Ltd | Construction | 2020 |
| Tldh Limited | Other services | 2019 |
| TLE Qualifications Ltd | Education | 2023 |
| TM Trading (N.I.) Limited | Construction | 2015 |
| TMB Electrics Limited | Construction | 2021 |
| TMC Maintenance Limited | Households | 2025 |
| TMK Contracts Limited | Construction | 2005 |
| TMK Livestock Ltd | Agriculture & fishing | 2016 |
| TMT Business Solutions Ltd | Wholesale & retail | 2026 |
| TMV Project Management Limited | Extraterritorial | 2005 |
| TN Trading Ltd | Professional & scientific | 2013 |
| Toals Bar Limited | Hospitality | 2020 |
| TOC Coaching Ltd | Professional & scientific | 2023 |
| Together Through Play CIC | Health & social care | 2025 |
| Togl Energy Limited | Professional & scientific | 2025 |
| Tohill Financial Services Limited | Financial services | 2026 |
| Toland Distribution Ltd | Agriculture & fishing | 2019 |
| Tollymore Property Services Limited | Real estate | 2021 |
| TOM FOX AQS Ltd | Other services | 2015 |
| TOM Nolan Motors Ltd | Wholesale & retail | 2023 |