| Geotest Ltd | Construction | 2018 |
| Gesners Property Management Ltd | Households | 2010 |
| GH Venue Ltd | Real estate | 2024 |
| Gift My Carer Ltd | Wholesale & retail | 2024 |
| Gillis Sports Management Limited | Education | 2024 |
| Gilly's School for Dogs Ltd | Other services | 2025 |
| Girls Know Ltd | Professional & scientific | 2025 |
| GKR Assets Ltd | Real estate | 2024 |
| GKR Health Care Services Ltd | Health & social care | 2023 |
| GKS Recruitment Ltd | Administrative & support | 2019 |
| Glade and Sky Ltd | Information & communication | 2023 |
| Glassology Limited | Manufacturing | 1999 |
| Global Construction Group Ltd | Construction | 2023 |
| Globearc Ltd | Information & communication | 2025 |
| Globus Business Limited | Administrative & support | 2017 |
| GLR Heating Ltd | Construction | 2014 |
| GLS Document Storage Ltd | Administrative & support | 2023 |
| GM Family Holding Limited | Financial services | 2026 |
| GM Smart Electronics Ltd | Wholesale & retail | 2019 |
| GMK Entreprise Ltd | Health & social care | 2015 |
| Gmodes Ltd | Real estate | 2025 |
| Go Green Taxis Ltd. | Transport & logistics | 2009 |
| Gobo Theatre Community Interest Company | Education | 2020 |
| Gobo Theatre Foundation | Administrative & support | 2010 |
| Godric Global Events and Promotion Ltd | Arts & recreation | 2025 |
| Golden Circle Chinese Ltd | Hospitality | 2024 |
| Golden Pillar Ltd | Real estate | 2020 |
| Golden Services Management Ltd | Transport & logistics | 2023 |
| Goodwill Developer Ltd | Construction | 2023 |
| Gourmet Food Trade Ltd | Wholesale & retail | 2025 |
| Grade Economy Ltd | Information & communication | 2025 |
| Grafioso Ltd | Professional & scientific | 2022 |
| Graham Waters Transport Ltd | Transport & logistics | 2017 |
| Grain Fumigation Services Ltd | Other services | 2005 |
| Grandridge Ltd | Real estate | 2025 |
| Grasshopper Labs Ltd | Information & communication | 2026 |
| Gratia Cura Residential Ltd | Health & social care | 2023 |
| Gravtech Solutions Ltd | Professional & scientific | 2024 |
| Great Towers Logistics Ltd | Water & waste | 2022 |
| Great Western Preservations Limited | Arts & recreation | 1986 |
| Great Western Restaurants Limited | Arts & recreation | 1990 |
| Great Western Retail Sales Limited | Arts & recreation | 1990 |
| Greaves IT Contracting Ltd | Information & communication | 2025 |
| Green Helm Ltd | Professional & scientific | 2026 |
| Green House Think Tank | Information & communication | 2015 |
| Green Turtle Media Ltd | Information & communication | 2022 |
| Greenbed Investments Ltd | Real estate | 2025 |
| Greendale Property Ltd | Real estate | 2017 |
| Greenough Legal Services Ltd | Professional & scientific | 2019 |
| Greenscape Group Ltd | Real estate | 2024 |
| Greenwood Guides Travel & Media Limited | Information & communication | 2019 |
| Greenworth Interiors and Carpentry Limited | Manufacturing | 2024 |
| Gregory Management Limited | Professional & scientific | 2012 |
| Griffin Petroleum Consulting Limited | Mining & quarrying | 1998 |
| Griffin Tail Lift Services Ltd | Manufacturing | 2026 |
| Grizzly’S Craft Ltd | Wholesale & retail | 2025 |
| Grove Farms (Harwell) Limited | Agriculture & fishing | 1996 |
| Gssech Ltd | Financial services | 2025 |
| Guffbox Games Ltd | Information & communication | 2021 |
| Guildhouse Games Ltd | Manufacturing | 2025 |
| Gupta & Sons Ltd | Wholesale & retail | 2022 |
| Guru Neem Karoli Baba Ltd | Real estate | 2025 |
| Gwtd Properties Limited | Real estate | 2019 |
| H H Developments Limited | Hospitality | 2007 |
| H&C ENT Ltd | Real estate | 2024 |
| H6 Capital Investments Ltd | Real estate | 2025 |
| Hadden Hill Community Golf Club Limited | Arts & recreation | 2006 |
| Hadden Hill Community Members Club Limited | Arts & recreation | 2006 |
| Halidon Services Ltd | Professional & scientific | 2019 |
| Hammond and Clark Landscaping and Construction Ltd | Construction | 2021 |
| Hand Architecture Limited | Professional & scientific | 2026 |
| Hannay Electrical Contractors Ltd | Construction | 2019 |
| Hansei Improvement Ltd | Professional & scientific | 2024 |
| Hantero Ltd | Real estate | 2024 |
| Happiness Hampers Ltd | Wholesale & retail | 2021 |
| Harion Marketing Ltd | Professional & scientific | 2025 |
| Haris Structural Consultancy Ltd | Professional & scientific | 2015 |
| Harley & Mylo Group Ltd | Construction | 2024 |
| Harrier Park M.C. Limited | Households | 1989 |
| Harrison-Rolls Investments Ltd | Real estate | 2024 |
| Harry's Offlicence & Takeaway Ltd | Wholesale & retail | 2025 |
| Harsiddhi Bhavani Ltd | Wholesale & retail | 2024 |
| Hartnett Carpentry & Joinery Limited | Construction | 2021 |
| Harwell Consulting Limited | Professional & scientific | 2007 |
| Harwell Consulting Services Ltd | Professional & scientific | 2019 |
| Harwell Medical Communications Ltd | Professional & scientific | 2021 |
| Harwell Oxford Developments (GP) Limited | Financial services | 2013 |
| Harwell Oxford Developments Limited | Financial services | 2013 |
| Haven Analytics Ltd | Professional & scientific | 2015 |
| Hawkspire Investments Ltd | Real estate | 2024 |
| Hawthorne Racing Services Ltd | Professional & scientific | 2025 |
| Hayer Property Estates Ltd | Real estate | 2024 |
| Hayes Construction & Design Ltd | Construction | 2019 |
| HE Space Operations Ltd | Administrative & support | 2020 |
| HEALTHSPACE21 Ltd | Other services | 2022 |
| Heart Safe Sport C.I.C. | Education | 2026 |
| Heatandflow Consultancy Limited | Professional & scientific | 2009 |
| Heaven Electrical Ltd | Construction | 2022 |
| Hedley Construction Ltd | Construction | 2012 |
| Hehe Property Ltd | Real estate | 2022 |