| Heritage Grain Trust | Education | 2020 |
| Hero Doctor Limited | Information & communication | 2017 |
| Heron Development Holdings Limited | Professional & scientific | 2019 |
| Heron Place Residents Association Limited | Households | 1972 |
| Herotech Ltd | Real estate | 2023 |
| Herschel Court (Oxford) Management Company Limited | Households | 1991 |
| Hertford College Design and Build Limited | Construction | 2020 |
| Hertford College Programmes | Education | 2010 |
| Hesarak Food Limited | Hospitality | 2025 |
| Hester Architects Limited | Professional & scientific | 1998 |
| Hester Interior Ltd | Wholesale & retail | 2023 |
| Hestia Architects Ltd | Construction | 2020 |
| Hestia Eghwe Limited | Real estate | 2023 |
| Hestia Enterprises Limited | Real estate | 2021 |
| Hestia Stewardship Ltd | Professional & scientific | 2021 |
| Heston Holdings Ltd | Wholesale & retail | 2016 |
| Hetherington Decorators Limited | Construction | 2008 |
| Hevad Care Ltd | Health & social care | 2023 |
| Hevad Group Ltd | Financial services | 2023 |
| Hexiqon Homes (Construction) Ltd | Construction | 2022 |
| Hexiqon Homes Ltd | Real estate | 2021 |
| Hextall Twiddy Limited | Professional & scientific | 2016 |
| HEY Guys Services Limited | Information & communication | 2023 |
| HEY HEY Media Ltd | Professional & scientific | 2023 |
| Heyford Biotech Integration Ltd | Professional & scientific | 2023 |
| Heyford Research Ltd | Professional & scientific | 2023 |
| Hezaside UK Ltd | Wholesale & retail | 2022 |
| HFZ Bucks Ltd | Hospitality | 2020 |
| HH Prop Co Limited | Real estate | 2025 |
| HHT Solutions Ltd. | Information & communication | 2001 |
| HI Tea @ Bakery Ltd | Hospitality | 2024 |
| Hi-Choice Limited | Other services | 2007 |
| HI4 Enterprises Limited | Information & communication | 2014 |
| HIC Sunt Dracones Ltd | Financial services | 2012 |
| Hicks & SON (Oxford) Limited | Real estate | 1943 |
| Hifdh Academy Ltd | Education | 2021 |
| High Altitude Wine Ltd | Wholesale & retail | 2024 |
| High Barn Developments Limited | Construction | 2012 |
| High Barn Elvendon Ltd | Real estate | 2025 |
| High Barn Estates Limited | Construction | 2021 |
| High Point Holidays LLP | | 2007 |
| High Point Holidays UK Limited | Administrative & support | 2026 |
| High Point Yachting Ltd | Professional & scientific | 2001 |
| High Ropes Oxford Ltd | Arts & recreation | 2011 |
| High TOR Capital 1 LLP | | 2024 |
| High TOR Capital Ltd | Professional & scientific | 2024 |
| Highbank Close Mangement Company Ltd | Households | 2012 |
| Higher Intellect Music Group Ltd | Information & communication | 2025 |
| Highfield Communication Consultancy Ltd. | Professional & scientific | 1998 |
| Highfield Communication Consultancy Trustee Limited | Professional & scientific | 2025 |
| Highfield Motors Limited | Wholesale & retail | 2003 |
| Hightec Solutions Limited | Information & communication | 2009 |
| Hightech IT Support Limited | Information & communication | 2013 |
| Highton Homes Limited | Real estate | 2006 |
| Hikari Estates Ltd | Real estate | 2025 |
| Hiking International Limited | Professional & scientific | 1985 |
| Hill END Outdoor Education Centre | Education | 2017 |
| Hill Farm (Marston) Limited | Agriculture & fishing | 2010 |
| Hill Rise (Woodstock) Management Company Limited | Households | 2025 |
| Hillcrest Colorectal Ltd | Health & social care | 2022 |
| Hillier Minerals Ltd | Manufacturing | 2024 |
| Hillside Cumnor Hill Limited | Households | 2001 |
| Hillside KH Management Company Ltd | Households | 2014 |
| Hillthorpes Limited | Professional & scientific | 2009 |
| Hilltop Academy Ltd | Education | 2018 |
| Hilltop Careers Ltd. | Real estate | 2018 |
| Hilltop Chauffeurs Limited | Transport & logistics | 2023 |
| Hilltop Education Services Ltd | Education | 2021 |
| Hilltop Houseware Co. Ltd | Wholesale & retail | 2023 |
| Hilltop Radiology Ltd | Health & social care | 2023 |
| Hilltop Veterinary Centre Limited | Professional & scientific | 2016 |
| HIM Barbers Limited | Other services | 2022 |
| Himac Limited | Professional & scientific | 2019 |
| Himalayan (Oxford) Ltd | Manufacturing | 2024 |
| Hindsight Consultancy Ltd | Professional & scientific | 2016 |
| Hinksey Heights Golf Ltd | Arts & recreation | 2020 |
| Hinksey Heights Partnership Limited | Real estate | 1971 |
| Hinksey Labs Ltd | Professional & scientific | 2024 |
| Hinksey Projects Limited | Manufacturing | 2018 |
| Hinksey Trail Regeneration C.I.C. | Education | 2020 |
| Hipler Partners LLP | | 2003 |
| HIR Cars Limited | Wholesale & retail | 2025 |
| Hiraeon Ltd | Transport & logistics | 2019 |
| Hiranur Ltd | Hospitality | 2023 |
| Historic Oxford Limited | Wholesale & retail | 2019 |
| Hitchcopse Ltd | Administrative & support | 2007 |
| Hivemind Productions Ltd | Arts & recreation | 2024 |
| HK Events Ltd | Hospitality | 2025 |
| HK1 Limited | Real estate | 2020 |
| HLD International Limited | Administrative & support | 2018 |
| HLR Foods Ltd | Hospitality | 2019 |
| HMB Associate Ltd | Administrative & support | 1998 |
| HMG Contracts Ltd | Construction | 2026 |
| HMZ Limited | Hospitality | 2017 |
| HNA Accountants Ltd | Professional & scientific | 2012 |
| Hnaenterpriseco.Uk Ltd | Wholesale & retail | 2026 |
| Hobbyquest Limited | Administrative & support | 1997 |
| HOCKEY21 Ltd | Information & communication | 2020 |
| Hodges & Lawrence Limited | Manufacturing | 1961 |
| Hodspeed Ltd | Wholesale & retail | 2023 |