| Grantham House Management Company Limited | Households | 2013 |
| Granville Court Residents Company Limited | Households | 1970 |
| Grayson Plumbing and Heating Ltd | Construction | 2022 |
| Green Cleen (South Oxfordshire) Limited | Households | 2011 |
| Green Life 2019 Limited | Administrative & support | 2019 |
| Green Narrowboats Ltd | Manufacturing | 2020 |
| Greencars Ltd | Wholesale & retail | 2023 |
| Greenome Bookings Ltd | Professional & scientific | 2021 |
| Greenpoint Strategy Ltd | Professional & scientific | 2015 |
| Greenscape In-Spires Garden Maintenance Ltd | Administrative & support | 2006 |
| Greenth Ltd | Wholesale & retail | 2020 |
| Greenway Builders (Oxford) Limited | Construction | 2003 |
| Gregs Garage (Galashiels) Ltd | Wholesale & retail | 2004 |
| Grenediche House Management Company Limited | Households | 1997 |
| Grid (Oxford) Limited | Financial services | 2017 |
| Gsaral Limited | Wholesale & retail | 2024 |
| GSM Healthcare Ltd | Health & social care | 2014 |
| Gurkha Village Oxford Ltd | Hospitality | 2012 |
| Gurnies Mews Management Limited | Households | 2009 |
| Guylian (UK) Ltd | Wholesale & retail | 2000 |
| GV Cleaning Home and Business Ltd | Administrative & support | 2024 |
| GV Cleaning Home Cleaning Services Ltd | Administrative & support | 2023 |
| H & R Services (Oxford) Limited | Construction | 2005 |
| H2W Customs Limited | Manufacturing | 2014 |
| Halbrook Group Limited | Professional & scientific | 2022 |
| Hall Training Systems Ltd | Arts & recreation | 2016 |
| Hallidays UK Properties Ltd | Real estate | 2018 |
| HALO22 Limited | Financial services | 2022 |
| HALO23 Ltd | Arts & recreation | 2023 |
| HALO24 Limited | Construction | 2023 |
| Hamble Yacht Care Limited | Other services | 2000 |
| Hampden Manor (Mill Street) Management Company Limited | Households | 2008 |
| Harcourt House Management Limited | Households | 2000 |
| Haus Digital Ltd | Professional & scientific | 2026 |
| Havdem Ltd | Wholesale & retail | 2025 |
| Hawker Aero Limited | Professional & scientific | 2024 |
| Hawridge Mews Management Company Limited | Households | 2007 |
| Hayley Faulkes Ltd | Other services | 2026 |
| Haynes Contracting Limited | Agriculture & fishing | 2009 |
| HBP Management Limited | Water & waste | 1985 |
| Hdelity Limited | Manufacturing | 2018 |
| Headington Heating and Plumbing Supplies Ltd | Wholesale & retail | 2017 |
| Health 9 Limited | Health & social care | 2024 |
| Health and Safety 4 Education Ltd | Education | 2020 |
| Heathfield Park Equestrian Limited | Agriculture & fishing | 2023 |
| Hebborn and SON Limited | Arts & recreation | 2019 |
| Hedrhservices Ltd | Wholesale & retail | 2025 |
| Hemley Properties Ltd | Real estate | 2025 |
| Henaud Developments Limited | Construction | 2007 |
| Henderson Design (Oxford) Ltd | Professional & scientific | 2008 |
| Hernes House (Oxford) Management Company Limited | Households | 2013 |
| Heron Architecture Ltd | Professional & scientific | 2025 |
| Hestia Design PM Ltd | Construction | 2024 |
| Heuristic Ventures Ltd | Professional & scientific | 2012 |
| Heva Energy Ltd | Information & communication | 2023 |
| Hexiqon Homes - 38LB Ltd | Real estate | 2025 |
| Heyford Rectory Freehold Company Limited | Real estate | 2018 |
| Hibrid Homes Limited | Real estate | 2024 |
| Hidden Lake Dorset Ltd | Other services | 2025 |
| Hilltop Harrogate Limited | Financial services | 2018 |
| Hindi Picture Limited | Information & communication | 1982 |
| Hinksey Sculling School Limited | Arts & recreation | 2003 |
| Hiperformant Ltd | Professional & scientific | 2025 |
| HL Munro Limited | Professional & scientific | 2026 |
| HMS Delivery Ltd | Transport & logistics | 2025 |
| Hobson Court Residents Association Limited | Households | 1994 |
| Hobson Curtis Films Limited | Information & communication | 2010 |
| Holiday Project Limited | Other services | 2025 |
| Holloway Farm Industrial Park Limited | Real estate | 1995 |
| Holyoake Management Company Limited | Households | 2004 |
| Homeowners 25 Limited | Real estate | 2018 |
| Hota Investments Limited | Real estate | 2022 |
| House of GIA Limited | Information & communication | 2002 |
| Houseman Construction Limited | Construction | 1999 |
| Howes Models Limited | Wholesale & retail | 1996 |
| HR Fitness Oxford Ltd | Extraterritorial | 2023 |
| HSR (Oxford) Limited | Real estate | 1999 |
| HSW Agency Limited | Professional & scientific | 2020 |
| Huckin & Co Ltd | Construction | 2021 |
| Huckle Advisory Ltd | Professional & scientific | 2026 |
| Hudson Architecture Studio Limited | Professional & scientific | 2016 |
| Hullo Aircrew Ltd | Administrative & support | 2017 |
| Hullo Ltd | Administrative & support | 2016 |
| Hustle HR Ltd | Information & communication | 2023 |
| HVJ Transport Limited | Professional & scientific | 2016 |
| Hyland Renovation Advice & Management Ltd | Professional & scientific | 2022 |
| Hyperfocus Films Ltd | Information & communication | 2008 |
| I S Homes Development Ltd | Construction | 2025 |
| I.H.S. Systems Limited | Administrative & support | 2007 |
| I24 Limited | Information & communication | 2022 |
| Ideald Limited | Professional & scientific | 2025 |
| IDS Decorators Limited | Construction | 2002 |
| Inclusive by Design Limited | Professional & scientific | 2022 |
| Indian Friends Kitchen Limited | Wholesale & retail | 2023 |
| Industrial Vision and Metrology Systems Limited | Wholesale & retail | 2000 |
| Industrial Vision Systems Ltd. | Manufacturing | 2000 |
| Infinitealoe UK Ltd | Wholesale & retail | 2017 |
| Infinity Scroll Limited | Information & communication | 2023 |
| Ingleby Paddocks Limited | Households | 2009 |
| Innspired Property Ltd | Real estate | 2024 |