| Hamblin Pianos Limited | Professional & scientific | 2009 |
| Hamblin Snack Bar Ltd | Hospitality | 2023 |
| Hamda Umer Limited | Wholesale & retail | 2026 |
| Hamilton House (Oxford) Residents Management Company Limited | Households | 2016 |
| Hamilton Patrick | Financial services | 2013 |
| Hammer and Co Capital Resources Limited | Professional & scientific | 2008 |
| Hammer-Hewstone Consulting Limited | Professional & scientific | 2006 |
| Hampdon Ltd | Real estate | 2025 |
| Hamptworth Estate (Solar) Limited | Real estate | 2012 |
| Hamsterzorb Limited | Arts & recreation | 2012 |
| HAN Commodities Limited | Real estate | 2014 |
| HAN Property Developments Limited | Real estate | 2021 |
| HAN Treasury Ltd | Financial services | 2020 |
| Hand Car Wash Specialists Ltd | Other services | 2023 |
| Hand Dryers Direct Limited | Extraterritorial | 2019 |
| Hands on Project Solutions Limited | Information & communication | 2006 |
| Handyman & Cleaner Services Ltd | Construction | 2022 |
| Handyman Oxfordshire Ltd | Construction | 2021 |
| Hanil Tube Holdings Limited | Professional & scientific | 2007 |
| Hanjira Limited | Other services | 2022 |
| Hankook Ltd | Wholesale & retail | 2023 |
| Hanley Management Ltd | Hospitality | 2016 |
| Hanlon Flooring Limited | Wholesale & retail | 2016 |
| Hannah Townsend Coaching Limited | Education | 2025 |
| Hanover Horseboxes Limited | | 1988 |
| Hanref Ltd | Wholesale & retail | 2024 |
| Hansby & Co Ltd | Construction | 2019 |
| Hanson Plumbing and Heating Limited | Extraterritorial | 2012 |
| Hansons Plumbing and Heating Ltd | Other services | 2016 |
| Haoke Technology Ltd | Information & communication | 2026 |
| Happy Cakes UK Limited | Manufacturing | 2009 |
| Happy Care Services Limited | Health & social care | 2019 |
| Happy Healthy Publishing Ltd | Information & communication | 2025 |
| Happyheartslifecoaching Ltd | Education | 2025 |
| HAQ Halal Butchers and Groceries Ltd | Wholesale & retail | 2024 |
| Haranberry Ltd | Health & social care | 2022 |
| Haras Caring Ltd | Health & social care | 2019 |
| Harberton Heights (Oxford) Management Company Limited | Households | 2007 |
| Harbor View Ltd | Hospitality | 2025 |
| Harding-Brown Holdings Ltd | Households | 2024 |
| Harefields Flats West Ltd | Households | 2025 |
| Harkledge Limited | Information & communication | 2024 |
| Harlech House Management Company Limited | Households | 1988 |
| Harley Street Breast Clinics Ltd | Health & social care | 2007 |
| Harley-James Electrical Services Ltd | Construction | 2020 |
| Harmony Heritage Limited | Professional & scientific | 2015 |
| Harmony Residents Association Limited | Households | 1989 |
| Harold Jackman Limited | Real estate | 1952 |
| Harper Automation Limited | Information & communication | 2025 |
| Harper Lane LOW Carbon Hydrogen Limited | Administrative & support | 2022 |
| Harpers Plumbing Services Ltd | Construction | 2013 |
| Harpin Tech Limited | Professional & scientific | 2012 |
| Harries-Jones Gaming Limited | Arts & recreation | 2024 |
| Harries-Jones Limited | Hospitality | 2014 |
| Harrington Alderman Ltd | Wholesale & retail | 2018 |
| Harrington Coaches Limited | Transport & logistics | 2007 |
| Harris 2014 Limited | Real estate | 2014 |
| Harris Enterprises Security Services Lock Division Limited | Administrative & support | 2004 |
| Harris JAN Property Services Limited | Real estate | 2020 |
| Harris Oxford Limited | Information & communication | 2007 |
| Harrowdown Limited | Professional & scientific | 2016 |
| Hartley Court (Oxford) Limited | Households | 2004 |
| Hartminster Limited | Professional & scientific | 2010 |
| Harvard Investments, LP | | 2015 |
| Harvest Hill Property Company Limited | Real estate | 2017 |
| Harvey 2011 Ltd. | Health & social care | 2019 |
| Harveys of Oxford Limited | Hospitality | 1994 |
| Hasan Armstrong Ltd | Information & communication | 2023 |
| Haseley Homes (Oxford) Ltd | Construction | 2009 |
| Hashmi Prestige Ltd | Wholesale & retail | 2026 |
| Hassan Wahla & Sons.Co. Ltd | Wholesale & retail | 2025 |
| Hassani and Sons Ltd | Health & social care | 2011 |
| Hathaway's Estate Agents Limited | Real estate | 2024 |
| Hatopy Ltd | Information & communication | 2025 |
| Haus of Contrology Ltd | Arts & recreation | 2025 |
| Haven Stays Property Management Ltd | Real estate | 2025 |
| Havi Architects Limited | Professional & scientific | 2024 |
| Hawes Construction Ltd. | Construction | 2006 |
| Hawkins & Riveiros Limited | Construction | 2003 |
| Hawkswell Estates Limited | Households | 1988 |
| Hawkswell House Residents Association Limited | Households | 1968 |
| Hawkwell Properties Limited | Real estate | 2016 |
| Hawridge Estates Limited | Real estate | 2016 |
| Hawridge Properties Limited | Real estate | 2016 |
| Hawthorns Developments Limited | Construction | 2020 |
| Haxez Ltd | Information & communication | 2015 |
| Hayat Care Ltd | Administrative & support | 2026 |
| Hayat Commerce Ltd | Wholesale & retail | 2026 |
| Hayat Foundation Limited | Education | 2010 |
| Haynes Digital Systems Ltd | Information & communication | 2025 |
| Hayns Oxford Property Ltd | Real estate | 2023 |
| HBJ Bars Limited | Hospitality | 2025 |
| HBZ Group Ltd | Information & communication | 2026 |
| Hccinitiative CIC | Health & social care | 2025 |
| HCK Bioscience Limited | Professional & scientific | 2025 |
| HCK Properties Limited | Real estate | 2016 |
| Hcpg Ltd | Administrative & support | 2014 |
| HCV Network Ltd | Professional & scientific | 2015 |
| HD Health Consulting Limited | Professional & scientific | 2026 |
| Hdent Ltd | Health & social care | 2023 |