| Helen's Way Apartments Management Company Limited | Households | 2001 |
| Helen's Wood Management Company Limited | Real estate | 2018 |
| Helena Kylie Limited | Wholesale & retail | 2025 |
| Helendale Limited | Wholesale & retail | 2008 |
| Helendale Properties Ltd | Real estate | 2025 |
| Helens Day to Day Ltd | Wholesale & retail | 2018 |
| Heliocycle Ltd | Water & waste | 2026 |
| Helios IT Ltd | Information & communication | 2001 |
| Helios Management & Efficiency Consulting Limited | Professional & scientific | 2019 |
| Heliraptor Limited | Administrative & support | 2021 |
| Helix Aviation Services Ltd | Transport & logistics | 2021 |
| Hella Innovation Ltd | Professional & scientific | 2015 |
| Hellfire Tattoo Club Ltd | Other services | 2025 |
| Hello Fone FIX Ltd | Wholesale & retail | 2025 |
| Helmsman Storage Solutions Limited | Manufacturing | 2013 |
| Helping Hands Daycare (Ballycastle) Ltd | Health & social care | 2023 |
| Helping Hands Daycare Ltd | Real estate | 2012 |
| Hemi BUS Limited | Wholesale & retail | 2025 |
| Hempyx Ltd | Wholesale & retail | 2025 |
| Henderson Clark Ltd | Financial services | 2025 |
| Heng Yuan Antrim Ltd | Hospitality | 2025 |
| Hengzhan Technology Co., Limited | Wholesale & retail | 2023 |
| Hennessy Medical Limited | Health & social care | 2011 |
| Hennessy Rentals Limited | Real estate | 2025 |
| Henrol Investment Ltd | Health & social care | 2023 |
| Henry Henry Productions Ltd | Information & communication | 2023 |
| Henry Hillock Ltd | Wholesale & retail | 2025 |
| Henry Joshua Michele Pohrer Ltd | Wholesale & retail | 2025 |
| Henry R. Ayton Engineering Services Limited | Manufacturing | 1983 |
| Henzy Properties Ltd | Real estate | 2022 |
| Henzylet Properties Ltd | Real estate | 2025 |
| Heojeoimport Ltd | Wholesale & retail | 2023 |
| Hepworth Executive Performance Ltd | Professional & scientific | 2025 |
| Hepzibah Ventures Limited | Hospitality | 2018 |
| HER Beautiful Curves Limited | Wholesale & retail | 2026 |
| Heracles Foundation Limited | Financial services | 2017 |
| Herbal Treasures Limited | Wholesale & retail | 2017 |
| Herbel Limited | Real estate | 2010 |
| Herbel Property Development Limited | Construction | 2014 |
| Herbel Restaurants Limited | Construction | 1980 |
| Herbert Corporate Holdings Limited | Professional & scientific | 2018 |
| Herbert Goulds Home Limited | Wholesale & retail | 2014 |
| Herbi Ltd | Wholesale & retail | 2022 |
| Herbison Fields Services Limited | Real estate | 2004 |
| Hercuglas Limited | Construction | 2022 |
| Hercules Outside Catering Ltd | Hospitality | 2022 |
| Hercules Protection NI Ltd | Administrative & support | 2021 |
| Herdman Electrical Ltd | Construction | 2026 |
| Herdsman Smart Technology Limited | Wholesale & retail | 2025 |
| Hereni | Professional & scientific | 2004 |
| Heritage Hideaways NI Limited | Real estate | 2025 |
| Heritage PAW Canine Services Limited | Agriculture & fishing | 2025 |
| Heritage Reproductions Ltd | Wholesale & retail | 2022 |
| Herniaconsult Limited | Wholesale & retail | 2023 |
| Hero Celebration Limited | Manufacturing | 2023 |
| Hero Management Ltd | Hospitality | 2023 |
| Heron Accountancy Solutions Ltd | Professional & scientific | 2026 |
| Heron Properties 51 Limited | Extraterritorial | 1998 |
| Heron View Property Ltd | Real estate | 2023 |
| Heroyoungee Limited | Wholesale & retail | 2023 |
| Herrise Capital Limited | Professional & scientific | 2026 |
| Herry Gill Ltd | Wholesale & retail | 2025 |
| Hersekat Ltd | Wholesale & retail | 2025 |
| Hertford Asset Management NO.1 Limited | Extraterritorial | 2021 |
| Hesion Enterprise Company Limited | Wholesale & retail | 2025 |
| Heslips Court Management Ltd | Households | 2015 |
| Hestify Ltd | Information & communication | 2025 |
| HEVIN2024 Ltd | Other services | 2024 |
| Hewitt & Gilpin Solicitors Limited | Administrative & support | 2009 |
| Hexagon Associates Limited | Information & communication | 2014 |
| Hexagon EYE Technologies Ltd | Information & communication | 2026 |
| Hexagon Metalworks Limited | Manufacturing | 2026 |
| Hexbomb Ltd | Wholesale & retail | 2017 |
| Hexpress Healthcare (NI) Limited | Wholesale & retail | 2021 |
| Hexsicon Limited | Health & social care | 2024 |
| HEY Roomie Ltd | Real estate | 2024 |
| Heyal Sales Limited | Wholesale & retail | 2025 |
| Heyn Engineering (NI) Limited | Manufacturing | 2000 |
| Heyn Group Limited | Professional & scientific | 1935 |
| Heyn HS Limited | Professional & scientific | 2014 |
| Heyn Limited | Administrative & support | 2015 |
| HF Northern Ireland LLP | | 2021 |
| Hfpa Ltd | Wholesale & retail | 2019 |
| HFY Care Group C.I.C. | Health & social care | 2023 |
| HH Bangor Limited | Hospitality | 2014 |
| HH Cherry Limited | Wholesale & retail | 2025 |
| Hhaccess Limited | Construction | 2023 |
| Hhdc Holdings Ltd | Administrative & support | 2023 |
| Hhdc Properties Limited | Real estate | 2025 |
| Hhdhike Ltd | Wholesale & retail | 2025 |
| HHG NO.10 Limited | Hospitality | 1971 |
| HHG NO.5 Limited | Hospitality | 2020 |
| HHG NO1. Limited | Hospitality | 2020 |
| HHG NO11. Limited | Hospitality | 2021 |
| HHG NO2. Limited | Hospitality | 2020 |
| HHG NO3. Limited | Hospitality | 2020 |
| HHG NO4. Limited | Hospitality | 2020 |
| HHG NO6. Limited | Hospitality | 2020 |
| HHI Building Products Limited | Extraterritorial | 1999 |
| Hhjhh Limited | Real estate | 2025 |