| Global Trusted Services Ltd | Information & communication | 2019 |
| GLS Commercial Properties Ltd | Real estate | 1977 |
| GLS HOMES4U Limited | Real estate | 2026 |
| GLS Property Care Ltd | Construction | 2026 |
| Glyn Davies Photo-Artist Limited | Arts & recreation | 2007 |
| GM Site Services Ltd | Professional & scientific | 2020 |
| Gmac Health Limited | Wholesale & retail | 2011 |
| GNO Enterprises Ltd | Wholesale & retail | 2019 |
| Godfrey Gate Management Company Limited | Households | 2005 |
| Gofal Gwynfyd Care CYF | Health & social care | 2020 |
| Golau Gobaith Light of Hope CIC | Other services | 2026 |
| Goldcharm Residential Limited | Construction | 2015 |
| Goldcharm Student Lettings Limited | Real estate | 2015 |
| Golden EYE Events Limited | Administrative & support | 2001 |
| Golden Prime Ltd | Wholesale & retail | 2021 |
| Golden Star Consultants Ltd | Information & communication | 2014 |
| Goldsec Limited | Real estate | 2011 |
| Golf MON Ltd | Arts & recreation | 2018 |
| Gordi Sumner Rope Access Limited | Manufacturing | 2016 |
| Gordon Playground Inspections Ltd | Professional & scientific | 2016 |
| Gorgie Road Edinburgh Limited | Construction | 2020 |
| Gorse Stacks Development Limited | Construction | 2002 |
| Goskies Ltd | Administrative & support | 2026 |
| GR Hair & Academy Ltd | Other services | 2025 |
| Grace Accountancy Services Ltd | Professional & scientific | 1999 |
| Grace Money Transfer Ltd | Financial services | 2016 |
| Gracion Services Limited | Administrative & support | 2025 |
| Grade Stream Ltd | Information & communication | 2024 |
| Grandemain Ltd | Wholesale & retail | 2021 |
| Gransha Catering Limited | Hospitality | 2019 |
| Gransha Consultancy Limited | Professional & scientific | 2016 |
| Gransha Lane Management Ltd | Households | 2024 |
| Grays Medical Consultancy Limited | Health & social care | 2019 |
| Grease Monkey Trading Limited | Wholesale & retail | 2018 |
| Gredam Limited | Administrative & support | 2019 |
| Green Renewables Connect Ltd | Professional & scientific | 2023 |
| Green Ridge Management Company (N.I.) Ltd | Extraterritorial | 2021 |
| Greenbay Apartments Limited | Construction | 1986 |
| Greenbay Homes Limited | Construction | 1985 |
| Greenbridge Innovations Limited | Administrative & support | 2005 |
| Greeno Brittonic Limited | Wholesale & retail | 2017 |
| Greenrent Limited | Real estate | 2019 |
| Greenside Solutions Limited | Administrative & support | 2019 |
| Greenway Healthcare (NI) Limited | Manufacturing | 2007 |
| Grey FM Ltd | Administrative & support | 2026 |
| Grey Knight Group Ltd | Construction | 2026 |
| Greyshift Solutions Limited | Wholesale & retail | 2025 |
| Greystone Donaghadee Ltd | Hospitality | 2020 |
| Griff Rowland Creative Limited | Information & communication | 2013 |
| Grizzly Golf Grips Ltd | Wholesale & retail | 2024 |
| Groomsport House Property Management Limited | Households | 1999 |
| Groomsport Nurseries Limited | Wholesale & retail | 2011 |
| Groomsport Playgroup Limited | Education | 2010 |
| Groomsport Road Mews Limited | Extraterritorial | 1985 |
| Grosvenor Garage (Menai Bridge) Ltd | Wholesale & retail | 2014 |
| Ground Services (NI) Ltd | Water & waste | 2016 |
| Ground UP Productions Limited | Administrative & support | 2005 |
| Group Electrical Ltd | Wholesale & retail | 2023 |
| Grove Crescent Stratford Limited | Construction | 2021 |
| Growing for Change CIC | Agriculture & fishing | 2023 |
| Grundlemontgomery Ltd | Other services | 2014 |
| GS Fireplace Installations Ltd | Construction | 2022 |
| GSW Software Ltd | Information & communication | 2012 |
| GT Bangor Limited | Hospitality | 2011 |
| GTR (NI) Ltd | Professional & scientific | 2007 |
| Guarding the Guard Limited | Health & social care | 2025 |
| Guided Partners Ltd | Professional & scientific | 2025 |
| Guillemot Pictures Ltd | Information & communication | 2024 |
| Guillemot Rental Ltd | Hospitality | 2017 |
| Guiobusmindteasers Ltd | Professional & scientific | 2012 |
| Gull Wing Films Limited | Information & communication | 2019 |
| Gwasanaeth Adfocatiaeth a Chynghori Gogledd Cymru | Health & social care | 1997 |
| Gwasanaethau Eiddo Dafydd CYF | Households | 2021 |
| Gwel Y Llan Management Company Limited | Real estate | 2016 |
| Gwennol CYF | Professional & scientific | 2024 |
| Gwilbach Ltd | Real estate | 2016 |
| Gwyn a Gwyn CYF | Real estate | 2018 |
| Gwyn Roberts Building (Bangor) Limited | Real estate | 1987 |
| Gwynant Limited | Hospitality | 1988 |
| Gwynedd Car and Van Sales Ltd | Wholesale & retail | 2026 |
| Gwynedd Motors Ltd | Wholesale & retail | 2021 |
| H F Owen Transport and Storage Limited | Transport & logistics | 2003 |
| H J Landscapes Ltd | Administrative & support | 2008 |
| H&J Dental Laboratory Ltd | Health & social care | 2021 |
| H3 Solutions Ltd | Real estate | 2021 |
| Habit Fitness Bangor Ltd | Arts & recreation | 2023 |
| Habite 2000 Limited | Extraterritorial | 1997 |
| Hadley Edge Investments Limited | Real estate | 2021 |
| Hafan Y Glyn Management Company Limited | Households | 2025 |
| Hair Regain Co Ltd | Other services | 2025 |
| Halo Golf Ltd | Arts & recreation | 2025 |
| Hamilton 1966 Limited | Extraterritorial | 2013 |
| Hamilton GAS Products Limited | Wholesale & retail | 2005 |
| Hamilton Morris Waugh Limited | Professional & scientific | 2006 |
| Hamilton Road Dental Care Limited | Health & social care | 2010 |
| Hampson Lewis Limited | Professional & scientific | 2002 |
| Hand Krafts Ltd | Wholesale & retail | 2025 |
| Handyhome Property Services Ltd | Construction | 2024 |
| Hanover Court Management Company Limited | Extraterritorial | 2001 |
| Hanover Financial (NI) Limited | Professional & scientific | 2016 |