| G.A.T. Properties Ltd | Construction | 2001 |
| G.C. Contracts 1988 Ltd | Construction | 2019 |
| G.J. Property (2021) Ltd | Real estate | 2021 |
| G.M.B Limited | Mining & quarrying | 2016 |
| G.O.N Cleaning Services Limited | Administrative & support | 2014 |
| G.P.S. Colour Graphics Limited | Manufacturing | 1912 |
| G.W Service's Belfast Limited | Manufacturing | 2024 |
| G.W. Monson & Sons Limited | Professional & scientific | 1977 |
| G1 Search Group Ltd | Administrative & support | 2024 |
| G2 Environmental Services Limited | Administrative & support | 2006 |
| G8 Retail Limited | Wholesale & retail | 2026 |
| GA EOT Company Limited | Financial services | 2024 |
| GA Prime Ltd | Health & social care | 2022 |
| Gaaf Limited | Financial services | 2020 |
| Gabriel Smyth Limited | Professional & scientific | 2020 |
| Gadd Group Health and Wellness Ltd | Arts & recreation | 2023 |
| Gadget Care NI Ltd | Wholesale & retail | 2024 |
| GADGET4U Ltd | Wholesale & retail | 2018 |
| Gael Linn Teoranta | | 1970 |
| Gaelchursai Limited | Education | 2011 |
| Gaelectric Green Energy Limited | Energy | 2013 |
| Gaelectric Natural Resources Limited | Energy | 2015 |
| Gaelfit Limited | Arts & recreation | 2022 |
| Gaelic League Belfast | Other services | 2026 |
| Gaelphoist CIC | Professional & scientific | 2023 |
| Gaelsoft Limited | Information & communication | 2014 |
| Gaelspóirt Béal Feirste Ltd | Education | 2025 |
| Gaelspóirt OÓC Ltd | Education | 2025 |
| Gaffney's Fashions Ltd. | Wholesale & retail | 2016 |
| Gaffney's Property Limited | Real estate | 2016 |
| Gaffprop Ltd | Real estate | 2025 |
| Gaia Smart Energy (NI) Limited | Construction | 2021 |
| GAIA777 Limited | Wholesale & retail | 2025 |
| Gaib Ltd | Financial services | 2018 |
| Gaiety Investments UK | Professional & scientific | 2020 |
| Gaillot Charrit Limited | Financial services | 2017 |
| Gain Forth Gym Limited | Arts & recreation | 2022 |
| Gaina Limited | Information & communication | 2023 |
| Gala Case Limited | Arts & recreation | 2015 |
| Galabox Technology Company Limited | Wholesale & retail | 2025 |
| Galacase Properties Limited | Real estate | 2023 |
| Galactico Soccer Limited | Arts & recreation | 2016 |
| Galanta Irish Art Limited | Wholesale & retail | 2016 |
| Galanta NO. 1 Limited | Real estate | 2012 |
| Galanta NO. 2 Limited | Real estate | 2012 |
| Galantas Irish Gold Limited | Mining & quarrying | 1997 |
| Galar Holdings Limited | Financial services | 2015 |
| Galar Ireland Ltd | Wholesale & retail | 2010 |
| Galaway Limited | Administrative & support | 2011 |
| Galaxy Fireworks Limited | Wholesale & retail | 1997 |
| Galaxy Nails & Spa Ltd | Other services | 2025 |
| Galaxy Trading Platform Limited | Wholesale & retail | 2025 |
| Galbally Properties Ltd | Professional & scientific | 2004 |
| Galena Hall Consulting Ltd | Professional & scientific | 2016 |
| Galena Project Consultancy Ltd | Professional & scientific | 2019 |
| Galexc Fiduciary Ltd | Financial services | 2025 |
| Galexc Ltd | Professional & scientific | 2025 |
| Galgorm Castle Education and Preservation Limited | Arts & recreation | 2024 |
| Galgorm Castle Estates Limited | Arts & recreation | 1994 |
| Galgorm Castle Holdings Limited | Professional & scientific | 2008 |
| Galgorm Manor Hotel Limited | Hospitality | 1993 |
| Galgorm Properties (1) Limited | Construction | 2002 |
| Galgorm Properties (2) Limited | Construction | 2002 |
| Galileo Empower (NI) Limited | Energy | 2023 |
| Gallagher Bros Belfast Ltd | Wholesale & retail | 2022 |
| Gallagher Films Ltd | Information & communication | 2018 |
| Gallaghers Bakehouse (NI) Ltd | Wholesale & retail | 2018 |
| Gallant KLK Ltd | Wholesale & retail | 2025 |
| Galldon Construction Ltd | Wholesale & retail | 2025 |
| Galley Energy Limited | Energy | 2013 |
| Gallopers Deli Ltd | Wholesale & retail | 2026 |
| Galtec Engineering Limited | Construction | 2008 |
| Galwally Mews Management Limited | Extraterritorial | 2008 |
| Galway Management Company Limited | Households | 2013 |
| Galway Park Management Company Limited | Extraterritorial | 1999 |
| Gamblestown LLP | | 2007 |
| Game Locker Events Ltd | Administrative & support | 2022 |
| Game of Thrones Tours Ltd | Administrative & support | 2014 |
| Gamecon Limited | Hospitality | 2023 |
| Gamourz XR Limited | Wholesale & retail | 2023 |
| Gamut World Ltd | Real estate | 2022 |
| Ganara Ltd | Wholesale & retail | 2025 |
| Ganaway Farms Limited | Agriculture & fishing | 2012 |
| Gancia Limited | Arts & recreation | 2023 |
| Ganges (NI) Ltd | Other services | 2013 |
| Gangnan Belfast Ltd | Hospitality | 2025 |
| Ganstron Ltd | Wholesale & retail | 2025 |
| Gaojing Ltd | Wholesale & retail | 2024 |
| Gaowna Ltd | Wholesale & retail | 2025 |
| GAP Architects Ltd | Construction | 2019 |
| GAP EPC Limited | Professional & scientific | 2025 |
| GAP PM Ltd | Professional & scientific | 2021 |
| GAP RE Limited | Professional & scientific | 2014 |
| Garage Ballygowan Ltd the | Wholesale & retail | 2005 |
| Garden Design Centre Limited | Administrative & support | 2015 |
| Gardenhill Properties Limited | Construction | 2007 |
| Gardiner Estates Limited | Real estate | 1961 |
| Gardiner Square Management Company Limited | Households | 2020 |
| Garelochhead Developments Limited | Real estate | 2019 |
| Gareth Mcauley Painting & Property Maintenance Ltd | Construction | 2024 |