| Herron's CFC (Rathfriland) Ltd | Hospitality | 2018 |
| Hershey Trade LP | | 2015 |
| HEY Shopper Ltd | Wholesale & retail | 2022 |
| HFC Ltd | Real estate | 2026 |
| HFS Engineering Limited | Manufacturing | 2003 |
| HGL Accountax Limited | Professional & scientific | 2010 |
| HGM Investments Ltd | Professional & scientific | 2021 |
| HH Glamping Ltd | Real estate | 2023 |
| Higgins & Murdock Limited | Construction | 2025 |
| Higgins Groundworks Contracts Ltd | Construction | 2018 |
| High Street Contracts Ltd | Construction | 2025 |
| Highwalk Construction Ltd | Construction | 2021 |
| Highwayman Coaches Ltd | Transport & logistics | 2018 |
| Hilary Mcdonald Coaching Ltd | Arts & recreation | 2022 |
| Hill Engineering Limited | Manufacturing | 1999 |
| Hill Farmers Ltd | Agriculture & fishing | 2011 |
| Hill House 100 Ltd | Other services | 2017 |
| Hill Street Store Limited | Professional & scientific | 2021 |
| Hillcrest Marine Ltd | Agriculture & fishing | 2026 |
| Hillcrest VFX Limited | Information & communication | 2020 |
| Hillhead Stud Farm Ltd | Agriculture & fishing | 2023 |
| Hillmount Cottages Service Company Limited | Real estate | 2004 |
| Hillside Properties (NI) Limtied | Construction | 2006 |
| Hillside Services (IRL) Ltd | Other services | 2023 |
| Hillspring Properties Limited | Real estate | 2017 |
| Hilltop Garage Services Ltd | Wholesale & retail | 2018 |
| Hilltown Community Association Limited | Health & social care | 1993 |
| Hilltown Tiles & Flooring Ltd | Wholesale & retail | 2016 |
| Hillview Eggs Ltd | Manufacturing | 2019 |
| Hillview Motors Ltd | Wholesale & retail | 2018 |
| Hilside Properties NI Ltd | Wholesale & retail | 2018 |
| Hiltec Designs Ltd | Professional & scientific | 2013 |
| HK Tiling Ltd | Construction | 2025 |
| HK Trading Group Ltd | Wholesale & retail | 2023 |
| HKA Contracts Limited | Wholesale & retail | 2021 |
| HKD Limited | Wholesale & retail | 2025 |
| HM Hire Ltd | Administrative & support | 2025 |
| HMK Core Holdings Limited | Financial services | 2026 |
| HMT Group Ltd | Transport & logistics | 2015 |
| HOH NI Limited | Other services | 2024 |
| Holdfast Limited | Administrative & support | 1965 |
| Holiday Traditions Limited | Wholesale & retail | 2020 |
| Holistic Space Ireland Ltd | Health & social care | 2024 |
| Hollow House Farms Limited | Agriculture & fishing | 2023 |
| Holmburg Import L.P. | | 2017 |
| Home Appliance Services (Ireland) Limited | Manufacturing | 2004 |
| Home Caravans Ltd | Wholesale & retail | 2023 |
| Home Claim Loss Assessors Limited | Professional & scientific | 2013 |
| Home VET NI Ltd | Professional & scientific | 2021 |
| Home-Start Newry & Mourne | Other services | 2005 |
| Homestyle Kitchens Bedrooms and Living Spaces Ltd | Manufacturing | 2023 |
| Honey Beest Ltd | Wholesale & retail | 2021 |
| HOP Fitness Limited | Arts & recreation | 2025 |
| HOP House Bangor Ltd | Hospitality | 2025 |
| Horizon Electrical Services (NI) Limited | Construction | 2004 |
| Horizon Mews Limited | Households | 2004 |
| Horse First Limited | Manufacturing | 2008 |
| Hospital Road Consultancy Ltd | Health & social care | 2022 |
| Host Angel Limited | Other services | 2018 |
| Host PM Limited | Professional & scientific | 2023 |
| Hot and Loaded Ltd | Hospitality | 2025 |
| Hot Yoga Newry Ltd | Arts & recreation | 2025 |
| Hourihan Medical Consulting Limited | Administrative & support | 2013 |
| House of Emunah Ltd | Other services | 2025 |
| House of Lara Limited | Manufacturing | 2018 |
| House of Murphy Limited | Wholesale & retail | 1999 |
| House of Treasure Ltd | Hospitality | 2022 |
| Housing Works (Development) Limited | Construction | 2023 |
| Housing Works (Ireland) Ltd | Construction | 2022 |
| HQ Bricklaying Ltd | Construction | 2018 |
| HQ Building Design Ltd | Professional & scientific | 2017 |
| HQ Groundworks & Plant Ltd | Construction | 2021 |
| Hub Packaging Holdings Ltd | Financial services | 2022 |
| Hub Packaging Ltd. | Wholesale & retail | 2013 |
| Hudson Building and Civil Ltd | Construction | 2020 |
| Hugh Mclaren Limited | Wholesale & retail | 2025 |
| Hughco Limited | Financial services | 2026 |
| Hughes Joinery & Development Limited | Construction | 2022 |
| Hughes Kitchens and Bedrooms Limited | Manufacturing | 2018 |
| Hughes Plastering & Drylining Ltd | Construction | 2020 |
| Hughpal Ltd | Manufacturing | 2020 |
| Hungry Ground Publishers Limited | Information & communication | 2019 |
| Hunters Lodge (Lurgan) Ltd | Extraterritorial | 2013 |
| Hurdicup Ltd | Manufacturing | 2026 |
| Husky Technical Services Ltd | Transport & logistics | 2009 |
| Hutch and Co Bespoke Homes Limited | Construction | 2023 |
| HWH Group Ltd | Hospitality | 2017 |
| Hy-Ten Ireland Limited | Manufacturing | 2020 |
| Hybrid Training NI Ltd | Arts & recreation | 2023 |
| Hyfive Ltd | Wholesale & retail | 2016 |
| Hylagen Newry Limited | Other services | 2025 |
| Hynes Motors Ltd | Wholesale & retail | 2022 |
| Hypercentral Ltd | Information & communication | 2020 |
| Hyperdale L.P. | | 2017 |
| Hyperfox Invest L.P. | | 2015 |
| Hyperprotect Ltd | Information & communication | 2020 |
| I AM Digital Group Ltd. | Professional & scientific | 2015 |
| I Cant Believe It's NOT N. I. Ltd | Wholesale & retail | 2025 |
| I DO Wedding Cars Limited | Administrative & support | 2012 |
| I M Stone Ltd | Other services | 2019 |