| G Noall Services Ltd | Construction | 2018 |
| G2 Consult Limited | Professional & scientific | 2009 |
| G3 Bdms Ltd | Professional & scientific | 2016 |
| Gabletek Limited | Manufacturing | 1990 |
| Gabria Limited | Professional & scientific | 2018 |
| Gaffar Enterprise Ltd | Wholesale & retail | 2026 |
| Gahantech Consulting Ltd | Information & communication | 2011 |
| Gaia Chem Limited | Manufacturing | 2014 |
| Garston Property Ltd | Construction | 2026 |
| Gavin Music LLP | | 2012 |
| GB Energy Solutions Ltd | Professional & scientific | 2023 |
| George Care Service Ltd | Transport & logistics | 2019 |
| George James Construction Ltd | Construction | 2018 |
| GET Stable Limited | Health & social care | 2011 |
| Ghost Interiors Property Developments Ltd | Construction | 2024 |
| Gibbons Services Ltd | Professional & scientific | 2026 |
| Gibbons Visual Ltd | Manufacturing | 2022 |
| Gilberts Lane Management Company Limited | Real estate | 2010 |
| Gilles Vallet Limited | Extraterritorial | 2012 |
| Gillian Margaret Tracey Ltd | Extraterritorial | 2025 |
| Ginger FOX Consulting Limited | Professional & scientific | 2015 |
| Ginger FOX Cycles Ltd | Manufacturing | 2017 |
| GIO Thompson Ltd | Wholesale & retail | 2023 |
| Glimmer and Growth Ltd | Health & social care | 2024 |
| Global Change Limited | Professional & scientific | 1996 |
| Global CTS Ltd | Administrative & support | 2015 |
| Global Electrical Solutions Ltd | Manufacturing | 2013 |
| Global EV Solutions Limited | Extraterritorial | 2019 |
| Global Innovators Ltd | Professional & scientific | 2015 |
| Global Thinking Limited | Real estate | 1992 |
| Glowcation Ltd | Hospitality | 2017 |
| GM 2 Energy Limited | Extraterritorial | 2014 |
| Go Green Autos Ltd | Wholesale & retail | 2018 |
| Go Motee Courier Services Limited | Transport & logistics | 2021 |
| Godfrey Farrier Services Ltd | Manufacturing | 2016 |
| Gold Stone Court Management Company Limited | Households | 2022 |
| Golden Canopy Limited | Professional & scientific | 2025 |
| Golden Manor Ltd | Information & communication | 2013 |
| Golden Services Care Limited | Health & social care | 2014 |
| Goldenzone Limited | Professional & scientific | 1995 |
| Golfworld Leisure Limited | Arts & recreation | 1995 |
| Goodrich Compliance Limited | Administrative & support | 2013 |
| Goosey Wick Farm Limited | Households | 2020 |
| Graci Limited | Real estate | 2017 |
| Graham Jones Pharmacy Limited | Health & social care | 1990 |
| Grange Court Business Park Management Company Limited | Households | 2017 |
| Granville Travel Ltd | Administrative & support | 2018 |
| Great British Mead Company Limited | Manufacturing | 2019 |
| Great Expectations Limited | Health & social care | 1990 |
| Grebe Consultants Limited | Professional & scientific | 2000 |
| Green & Stripey Limited | Other services | 2020 |
| Green Enterprise Oxford Ltd | Wholesale & retail | 2015 |
| Green Farm Grafton Ltd | Agriculture & fishing | 2021 |
| Green Metropolis Ltd | Administrative & support | 2019 |
| Greentrack Coaching & Consulting Ltd | Professional & scientific | 2025 |
| Greystone Accountants Limited | Professional & scientific | 2026 |
| Greystone Equity Group Limited | Financial services | 2025 |
| Grove Barbers Ltd | Other services | 2025 |
| Grove Body Repairs Ltd | Wholesale & retail | 2021 |
| Grove Car Body Repairs Limited | Wholesale & retail | 1985 |
| Grove Computer Services Ltd | Wholesale & retail | 2010 |
| Grove Couriers Limited | Transport & logistics | 2021 |
| Grove Geeks Limited | Information & communication | 2013 |
| Grow-Re-Grow Ltd | Wholesale & retail | 2020 |
| Growl Films Limited | Information & communication | 2017 |
| Growl Property Ltd | Real estate | 2024 |
| GRT Management Ltd | Professional & scientific | 2008 |
| Guides for Brides Ltd. | Information & communication | 2000 |
| Gunpoint Oxford Limited | Construction | 2007 |
| GUY Simmons Property Consultancy Ltd | Real estate | 2020 |
| H.G.C. Scaffolding (Oxford) Limited | Construction | 1988 |
| Habit NOW Limited | Professional & scientific | 2025 |
| HAD Productions Limited | Information & communication | 2010 |
| Haffin Investments Ltd | Construction | 2026 |
| Hair & Beyond Training Ltd | Education | 2024 |
| Hair by Boutique Ltd | Other services | 2025 |
| Haist Limited | Professional & scientific | 2017 |
| Halford Psychology Ltd | Health & social care | 2014 |
| Hall TC Limited | Agriculture & fishing | 2024 |
| Hands Down Circus Ltd | Arts & recreation | 2019 |
| Hangar 5 Ltd | Information & communication | 2024 |
| Hannaby Developments Limited | Construction | 1986 |
| Hannah Ford Limited | Administrative & support | 2011 |
| Hanney Community PUB Ltd | Hospitality | 2014 |
| Hanney Glazed Limited | Construction | 2016 |
| Hardcastle Limited | Construction | 1989 |
| Harewood Management Services Limited | Real estate | 2025 |
| Hargun Enterprises Ltd | Wholesale & retail | 2020 |
| Harmlyn Motor Spares Ltd | Wholesale & retail | 2025 |
| Hartyn Property Group Ltd | Financial services | 2025 |
| Harvest Hill Holdings Ltd | Real estate | 2025 |
| Harwood Finance Limited | Real estate | 1963 |
| Hassh MPL Ltd | Wholesale & retail | 2026 |
| HAT Media Services Limited | Professional & scientific | 2019 |
| Hatton Garden Developments Limited | Construction | 2026 |
| Hausy Ltd | Manufacturing | 2025 |
| Haven GB Healthcare Limited | Health & social care | 2024 |
| Hayley Claringbould EP Ltd | Education | 2014 |
| Haynes of Challow Limited | Wholesale & retail | 1971 |
| Hazel Logistics Services Ltd | Transport & logistics | 2026 |