| Hazeley 2 Ltd | Construction | 2026 |
| Hazeley Ltd | Real estate | 2016 |
| HCS Witney Ltd | Information & communication | 2017 |
| HD Timber Construction Limited | Construction | 2023 |
| HDH Projects Limited | Construction | 2026 |
| Headboards & Ottomans Ltd | Manufacturing | 2022 |
| Healthchords Ltd | Health & social care | 2026 |
| Healthlab Limited | Health & social care | 2016 |
| Healthlab Online Limited | Health & social care | 2017 |
| Healthplus Innovations Limited | Public administration | 2024 |
| Healthsaas UK Limited | Information & communication | 2012 |
| Healthwatch Oxfordshire | Health & social care | 2013 |
| Heart Mind Body Ltd | Professional & scientific | 2024 |
| Heartwood Furniture & Joinery Limited | Manufacturing | 2018 |
| Heat & Power Group Limited | Financial services | 2023 |
| Heat & Power Services Limited | Administrative & support | 1997 |
| Heat Pump Consultant Ltd | Construction | 2014 |
| Heavenly Tarts LLP | | 2024 |
| Hedges Investments Limited | Real estate | 2020 |
| Heidi Black HR Ltd | Administrative & support | 2020 |
| Helicon Heights LLP | | 2018 |
| Hello Data Ltd | Information & communication | 2017 |
| Hello Housekeeping Ltd | Administrative & support | 2024 |
| HEM Matrix Limited | Transport & logistics | 2023 |
| Hemcal Limited | Financial services | 2025 |
| Hemmings Heritage Machinery and Mechanics Ltd | Manufacturing | 2026 |
| Hemmings Houses Limited | Real estate | 2025 |
| Hendeca Ltd | Professional & scientific | 2015 |
| Henman Building Services Limited | Construction | 2018 |
| Henry | Education | 2009 |
| Henry Atkin Gunmakers Limited | Manufacturing | 2006 |
| Henry Elliston Financial Planning Limited | Financial services | 2021 |
| Henry Liddon Court (Management) Limited | Households | 2014 |
| Henry Mccarty Holdings Ltd | Real estate | 2020 |
| Henry's (Hospitality) UK Limited | Hospitality | 2023 |
| Hensington Court Residents Company Limited | Households | 1983 |
| Heritage Motor Parts Limited | Professional & scientific | 2002 |
| Heritage Sports Management Ltd | Arts & recreation | 2022 |
| Heronsgate 7 Limited | Wholesale & retail | 2016 |
| Hewitt Consulting Services Ltd | Information & communication | 1996 |
| Hexagon Business Centres Limited | Administrative & support | 2011 |
| Hexnub Limited | Professional & scientific | 2015 |
| Hexnub Old LP | | 2014 |
| Hey-Day Communications Ltd | Professional & scientific | 2016 |
| Heyce UK Ltd | Wholesale & retail | 2023 |
| HFF Build Ltd | Construction | 2025 |
| Hfso Ltd | Professional & scientific | 2024 |
| HG Building Innovations Ltd | Construction | 2025 |
| HH Property Holding Limited | Financial services | 2016 |
| HH Property Trading Limited | Real estate | 2013 |
| Hicksdesign Limited | Information & communication | 2007 |
| High Sheldon Residents Association Limited | Households | 1990 |
| Hilary Malcolm Hawkins Ltd | Extraterritorial | 2024 |
| Hill & Haines (Property) Limited | Construction | 2000 |
| Hill Grove Family Farm Limited | Agriculture & fishing | 1969 |
| Hillbrook Enterprises Ltd | Real estate | 2025 |
| Hillbrook Trading Ltd | Construction | 2015 |
| Hillhouse Rural Enterprises Limited | Wholesale & retail | 2010 |
| Hillier Accountancy Limited | Professional & scientific | 2017 |
| Hillside Hideaways Limited | Real estate | 2020 |
| Hinksey Hill Woodland Company Limited | Agriculture & fishing | 2003 |
| Hipsterra Ltd | Wholesale & retail | 2025 |
| Hirate Energy Limited | Manufacturing | 2023 |
| Hitchcock Woodworks Ltd | Manufacturing | 2012 |
| HK Taxi & Chauffeur Services Limited | Transport & logistics | 2024 |
| Hodge Building Services Ltd | Construction | 2025 |
| Holden Aviation Limited | Other services | 2023 |
| Holentrix Ltd | Information & communication | 2025 |
| Holiday Letting Services Limited | Administrative & support | 2009 |
| Holifield Decorators Ltd | Construction | 2021 |
| Holland Wholesale Trading Limited | Wholesale & retail | 2019 |
| Hollands Wine Company Limited | Manufacturing | 2023 |
| Home Farm Consultancy Limited | Professional & scientific | 2021 |
| Home Native Holdings Ltd | Financial services | 2018 |
| Home Native Ltd | Wholesale & retail | 2015 |
| Home WIN Shuffle Ltd | Information & communication | 2025 |
| Homegrown Timber (Rail) Limited | Agriculture & fishing | 2000 |
| Homegrown Timber Group Limited | Extraterritorial | 2016 |
| Homegrown Timber Ltd | Agriculture & fishing | 2010 |
| Homely Furniture 2 Go Ltd | Wholesale & retail | 2019 |
| HOMES2 Group Ltd | Financial services | 2018 |
| HOMES2KEEP Ltd | Real estate | 2018 |
| Homestyle Plastics Limited | Construction | 2001 |
| Honeybee Care at Home Ltd | Health & social care | 2023 |
| Honeycomb Technologies Limited | Information & communication | 2006 |
| Honor Close (Kidlington) Management Company Limited | Real estate | 1980 |
| Honourable Productions Limited | Administrative & support | 2025 |
| Hooked on Music Ltd | Arts & recreation | 2023 |
| Hopescreative Ltd | Professional & scientific | 2022 |
| Hopkins Construction (Oxford) Limited | Construction | 2011 |
| Hopkins Plant Hire Limited | Extraterritorial | 2009 |
| Hopper Group Ltd | Real estate | 2024 |
| Hopton Court Estate Limited | Hospitality | 2024 |
| Horan Construction Services Limited | Construction | 1997 |
| Horizon Analytics Limited | Professional & scientific | 2025 |
| Horizon Leap Innovations Ltd | Information & communication | 2023 |
| Horizon Medical Consultancy Limited | Professional & scientific | 2014 |
| Horne Building Services (Oxford) Limited | Construction | 2005 |
| Hottea Mama Ltd | Wholesale & retail | 2017 |
| House 42 Ltd | Real estate | 2021 |