| Global Equipment Trading Ltd | Wholesale & retail | 2020 |
| Global Training and Education Centre (Gtec) Ltd | Education | 2017 |
| Gmcg Piping Design Limited | Professional & scientific | 2017 |
| GMG Drywall Limited | Construction | 2016 |
| GN Investment Holdings Ltd | Real estate | 2026 |
| Go Wild Adventure Outdoors Ltd | Education | 2026 |
| Good Help Project Ltd | Health & social care | 2024 |
| Gortlee Sales & Hire Ltd | Administrative & support | 2025 |
| Gortnaghey Management Company Limited | Real estate | 2006 |
| Gracemount Limited | Real estate | 2001 |
| Gracie Catering Limited | Hospitality | 2024 |
| Graft Speciality Coffee Ltd | Hospitality | 2024 |
| Green Architecture Ltd | Professional & scientific | 2013 |
| Green Globe Resources Ltd | Water & waste | 2013 |
| Greysteel Limited | Construction | 2011 |
| Greystone Gardens Management Company Limited | Households | 2026 |
| Grianan Contracts Ltd | Construction | 2020 |
| Grimes Urology Limited | Health & social care | 2022 |
| Groogans Ltd | Wholesale & retail | 2017 |
| Grovehill Property Limited | Real estate | 2012 |
| GS Chauffeur Ireland Ltd | Transport & logistics | 2025 |
| GT Quarries Ltd | Mining & quarrying | 2020 |
| Guild Cafe Ltd | Hospitality | 2013 |
| Guildhall Press | Information & communication | 2002 |
| Guildhall Recycled Fashion Limited | Education | 2015 |
| Gulfstream Marine Limited | Manufacturing | 2006 |
| H M L Plant & Skip Hire Limited | Wholesale & retail | 1993 |
| Halo Pet Products Limited | Extraterritorial | 2008 |
| Hambro Storm Ltd | Wholesale & retail | 2008 |
| Hampson Harvey LLP | | 2019 |
| Hanna and Co Accountants Derry Ltd | Professional & scientific | 2021 |
| Harkin Electrical Limited | Construction | 2025 |
| Harkin Media Limited | Professional & scientific | 2025 |
| Harkitech Ltd | Information & communication | 2022 |
| Harman Fine Furnishers & Co | Wholesale & retail | 2017 |
| Harpers Quay Car Park Limited | Transport & logistics | 2018 |
| Hass Investment Properties Limited | Administrative & support | 2016 |
| Hasson Motors Ltd | Wholesale & retail | 2026 |
| Hatmore Piping & Design Limited | Professional & scientific | 2018 |
| Haus Eight Films Ltd | Information & communication | 2012 |
| Have Your Tomorrow's (Hurt) | Education | 2008 |
| Hawthorn Heights Ltd | Construction | 2007 |
| Hayesbank Limited | Professional & scientific | 2019 |
| Hazlett Timber Products Ltd | Manufacturing | 2008 |
| Headdial UK Limited | Information & communication | 2026 |
| Healex Systems (UK) Limited | Information & communication | 2011 |
| Health Hub Professionals NI Ltd | Other services | 2018 |
| Healthwise (N.I.) Limited | Wholesale & retail | 2001 |
| Henry's Tiles & Bathrooms Ltd. | Wholesale & retail | 2011 |
| Herbert Place Properties Ltd | Real estate | 2024 |
| Hetherington Plant Sales NI Ltd | Construction | 2025 |
| Hidden Variable Limited | Professional & scientific | 2023 |
| Higgins Property Developments Limited | Extraterritorial | 2007 |
| High Risk Safety Limited | Professional & scientific | 2016 |
| Hightec Services Limited | Professional & scientific | 2017 |
| Hilltop Day Nursery (Beragh Hill) Ltd | Other services | 2009 |
| Hillvalley Limited | Real estate | 2013 |
| Hive Cancer Support | Education | 2018 |
| Hive Digital Studios Community Interest Company | Information & communication | 2016 |
| Hogan Properties (Park Avenue) Ltd | Real estate | 2016 |
| Hold Co 4416 Ltd | Real estate | 2022 |
| Holly Avenue Company Limited | Administrative & support | 2020 |
| Holly Avenue Holdings Limited | Financial services | 2025 |
| Holm Life Limited | Extraterritorial | 2010 |
| Holm N.I. Limited | Extraterritorial | 2010 |
| Homebird (N.I.) Ltd | Hospitality | 2013 |
| Hookline Syndicate Ltd | Wholesale & retail | 2025 |
| Hospital at Home Solutions Ltd | Manufacturing | 2025 |
| Hppl Holdings Ltd | Real estate | 2024 |
| Hppl OP Co Ltd | Hospitality | 2024 |
| HS Renewable Energy Ltd | Construction | 2021 |
| Hubron Management Company Ltd | Households | 2024 |
| Hugh Lynch HL Plastics Limited | Construction | 2025 |
| Hungry Apple 2 Limited | Hospitality | 2015 |
| Hungry Jazz Ltd | Hospitality | 2025 |
| Hutchy Brothers Ltd | Construction | 2019 |
| Ibreastfeed CIC | Information & communication | 2020 |
| Icon Ebusiness Limited | Information & communication | 2001 |
| Ifsni Limited | Wholesale & retail | 2024 |
| Iland Spritz Ltd | Manufacturing | 2025 |
| Image Branding Limited | Manufacturing | 2002 |
| Imagine Derry Limited | Information & communication | 2021 |
| Iman Elshafie Engineering Ltd | Professional & scientific | 2026 |
| IMB Science Consultancy Ltd | Professional & scientific | 2025 |
| Imcoe Properties Ltd | Real estate | 2026 |
| India House Limited | Hospitality | 2005 |
| Inish Supplies NI Ltd | Wholesale & retail | 2025 |
| Inish Tree Services Ltd. | Agriculture & fishing | 2017 |
| Inishaven Ltd | Administrative & support | 2020 |
| Inishowen Motors (UK) Limited | Administrative & support | 2019 |
| Inner City Capital Projects Ltd | Construction | 2024 |
| Innovate-Ni Ltd | Professional & scientific | 2016 |
| Instant Hoses (N.I.) Limited | Extraterritorial | 2011 |
| Intrinsic Interiors Limited | Manufacturing | 2020 |
| Intsys Solutions Ltd | Information & communication | 2021 |
| Iona BED and Breakfast Ltd | Hospitality | 2019 |
| Iona Enterprises | Real estate | 1999 |
| Ireland Retail Ltd | Wholesale & retail | 2023 |
| Irish Horse and Pony Racing Association | Arts & recreation | 2024 |
| Irwin Tyres Ltd | Wholesale & retail | 2017 |