| G C Interiors Oxford Limited | Wholesale & retail | 1983 |
| G C Wantage Limited | Transport & logistics | 2025 |
| G Clayton Properties Limited | Real estate | 2015 |
| G Dixon Dairies Limited | Wholesale & retail | 2013 |
| G F Publications Limited | Information & communication | 2015 |
| G Khutan Consulting Ltd | Professional & scientific | 2024 |
| G L C E Limited | Professional & scientific | 2004 |
| G&N Oxford Ltd | Hospitality | 2025 |
| G&T Executive Ltd | Transport & logistics | 2012 |
| G&T Partners Ltd | Professional & scientific | 2023 |
| G. Casserly and Sons Limited | Construction | 2006 |
| G. F. Cross & Sons (Holdings) Limited | Construction | 2019 |
| G. F. Cross & Sons Limited | Construction | 2003 |
| G20 Garden Events Ltd | Other services | 2025 |
| G3 Catering Ltd | Hospitality | 2011 |
| G51 Scaffolding Services Limited | Construction | 2023 |
| G7 Investment Ltd | Real estate | 2021 |
| Gabriella Designs Limited | Manufacturing | 1995 |
| Gadgets Corner Limited | Wholesale & retail | 2025 |
| Gaia Ltd | Information & communication | 2017 |
| Gaia Media Management Limited | Administrative & support | 2002 |
| Gaiauk Ltd | Wholesale & retail | 2018 |
| Gaims Ltd | Education | 2025 |
| Gain Solutions Limited | Administrative & support | 2022 |
| Gaisford Groundworks & Civils Ltd | Construction | 2024 |
| Gajatrans Ltd | Transport & logistics | 2017 |
| GAL Hope Inspired Community Interest Company | Health & social care | 2024 |
| Galaxie Hotels Limited | Hospitality | 2024 |
| Galaxy Foods 1 Limited | Hospitality | 2023 |
| Galent Consultancy Ltd | Administrative & support | 2010 |
| Galenyte Ltd. | Manufacturing | 2024 |
| Gallagher (M&E) Supplies Limited | Wholesale & retail | 2016 |
| Gallery Bouldering Ltd | Arts & recreation | 2022 |
| Galliard Properties Limited | Real estate | 1986 |
| Gallivan Investments Ltd | Real estate | 2022 |
| Galvani-Silva Limited | Information & communication | 2018 |
| Gama Security Limited | Administrative & support | 2008 |
| Gambit BIO Ltd | Manufacturing | 2021 |
| Gametech Consulting Limited | Information & communication | 2017 |
| Gamma Portfolio Ltd | Real estate | 2022 |
| Gamma RW Limited | Other services | 2014 |
| GAN Advisory Services Limited | Professional & scientific | 2013 |
| GAO Express Oxford Ltd | Hospitality | 2026 |
| Garage Architecture Studio Ltd | Information & communication | 2022 |
| Gardeners Arms North Parade Ltd | Hospitality | 2025 |
| Gardens for Good Ltd | Administrative & support | 2022 |
| Garnet Imaging Limited | Health & social care | 2019 |
| Garneys Limited | Information & communication | 2023 |
| Garrad & Garrad Ltd | Real estate | 2019 |
| Garry Property Limited | Real estate | 2017 |
| Garsington PUB Ltd | Hospitality | 2025 |
| Garswood Trust Nominees Limited | Administrative & support | 2010 |
| Garvin-Burns Limited | Financial services | 2020 |
| Gary Newsham Carpentry & Construction Limited | Construction | 2005 |
| Gary Walter Plumbing and Heating Limited | Construction | 1999 |
| Gateway Estates Limited | Real estate | 1978 |
| Gateway Films Limited | Information & communication | 2005 |
| Gather & Grow Events Ltd | Professional & scientific | 2019 |
| Gatineau Holdings Limited | Hospitality | 2022 |
| Gatineau Limited | Wholesale & retail | 2006 |
| Gazechim Composites UK Limited | Professional & scientific | 1974 |
| GB Anaesthetics Limited | Health & social care | 2016 |
| GC DE Luca Consulting Ltd | Health & social care | 2022 |
| GCC Builder Ltd | Construction | 2025 |
| GCO Properties Limited | Real estate | 2019 |
| GCP Equipment Limited | Professional & scientific | 2009 |
| GCR Education Limited | Education | 2018 |
| GDA Saini Ltd | Hospitality | 2026 |
| GDS Construction Limited | Construction | 2013 |
| Geds Studio Ltd | Information & communication | 2026 |
| GEE & Wyatt Properties Limited | Real estate | 2014 |
| Gelders Crescent Management Company Limited | Households | 2024 |
| Gemalmaz Tech Ltd | Wholesale & retail | 2026 |
| Gemini Consulting Solutions LLP | | 2006 |
| General Capital Advisory Partners (Gcap) LLP | | 2023 |
| Generic Music Services Ltd | Arts & recreation | 2022 |
| Genesis Business Consultants Limited | Professional & scientific | 2023 |
| Genfluence Consulting Ltd | Professional & scientific | 2026 |
| Genicko Consultancy Limited | Professional & scientific | 2003 |
| Genomex Ltd | Professional & scientific | 2016 |
| Genomic Medicine Services Ltd | Professional & scientific | 2018 |
| Genomics Limited | Professional & scientific | 2014 |
| Genscien UK Limited | Real estate | 2022 |
| Genscript Biotech (UK) Limited | Professional & scientific | 2021 |
| Gentle Density Developments Limited | Real estate | 2025 |
| Gentlemens Barbers Oxford Ltd | Other services | 2016 |
| Genturam Rental Company Limited | Real estate | 2022 |
| GEO - Trade & Consultancy Limited | Wholesale & retail | 2016 |
| Geomid Consulting Ltd | Information & communication | 2012 |
| George Oxford Hotel Ltd | Hospitality | 2016 |
| George Henry & Co.(Eynsham)Limited | Real estate | 1956 |
| George Irvine Fine Art Ltd | Arts & recreation | 2015 |
| George Mcgavin Ltd | Information & communication | 2012 |
| George Ronald Publisher Limited | Information & communication | 1984 |
| George's Marvellous Medicine Limited | Professional & scientific | 2014 |
| Georgeous Homes Ltd | Real estate | 2024 |
| Georgia Burt Architecture Limited | Professional & scientific | 2020 |
| German-Uk Student Conference C.I.C. | Administrative & support | 2026 |
| GET Go Limited | Other services | 2009 |
| GET ME Pampered Limited | Other services | 2017 |