| Greentec Energy Limited | Administrative & support | 2011 |
| Greentouch Technologies (UK) Limited | Wholesale & retail | 2017 |
| Greenville & Company Limited | Administrative & support | 2014 |
| Gregg Morris Consultants Limited | Real estate | 2013 |
| Greybird Solutions Limited | Agriculture & fishing | 1997 |
| Grian Limited | Information & communication | 2016 |
| Griffiths Ventures Limited | Extraterritorial | 2015 |
| Grigas Consultancy Ltd | Construction | 2019 |
| Grimsdells Lane (Management) Limited | Households | 2019 |
| Group Consulting Ltd | Professional & scientific | 2026 |
| Group Effort Foundation Ltd | Education | 2022 |
| Group Effort Ltd | Education | 2024 |
| Grove Farm Two Management Limited | Households | 2023 |
| Grovebury Farm Close (LB) Management Company Ltd | Households | 2023 |
| Grovepond Limited | Real estate | 2011 |
| Grover & Olufsen Ltd | Information & communication | 2017 |
| Growild Ltd | Information & communication | 2020 |
| GRS Systems Limited | Information & communication | 2026 |
| GRT Fit Limited | Arts & recreation | 2019 |
| GS Plumbing & Heating (Leighton Buzzard) Ltd | Construction | 2021 |
| GS5 Tech Limited | Information & communication | 2023 |
| GSB MK12 Limited | Real estate | 2025 |
| GU6IX Limited | Professional & scientific | 2020 |
| Guardian Internet Support Services (UK) Ltd. | Information & communication | 2001 |
| Gulliford Development Ltd | Professional & scientific | 2016 |
| GYA Decoration Ltd | Construction | 2016 |
| GZB Mechanical Services Ltd | Construction | 2025 |
| H Hunt Property Ltd | Extraterritorial | 2021 |
| H JAY Limited | Professional & scientific | 2017 |
| H T SAH Ltd | Professional & scientific | 2016 |
| H. & H.S. Vale Limited | Agriculture & fishing | 1996 |
| H.B.E. Facilities Limited | Administrative & support | 2019 |
| H.B.E. Services Limited | Manufacturing | 2008 |
| H.H.F.C. Management Services Limited | Arts & recreation | 1997 |
| Hadencastle Limited | Professional & scientific | 1999 |
| Hadland Imaging Limited | Manufacturing | 2009 |
| Haigh Technology Consulting Ltd | Information & communication | 2022 |
| Haina Ltd | Health & social care | 2022 |
| Hair-Style by Magda Limited | Other services | 2015 |
| Halcyon Rail Limited | Professional & scientific | 2025 |
| Hall and Benson Limited | Real estate | 2013 |
| Halley Mews Management Company Ltd | Households | 2023 |
| Hamilton Project Partners Limited | Information & communication | 2012 |
| Hammerdown ALL in Ltd | Professional & scientific | 2023 |
| Hammond Mortgage Services Ltd | Financial services | 2024 |
| Hampden Hall Management Limited | Households | 2005 |
| Hampstone Limited | Professional & scientific | 2006 |
| Hampton Gate Limited | Real estate | 2013 |
| Hamptons Estates Limited | Real estate | 1986 |
| Hancott Homes Ltd | Real estate | 2019 |
| Hand for Caring Ltd | Health & social care | 2025 |
| Hanna Instruments Limited | Wholesale & retail | 1987 |
| Hannah Duncan Investment Content Ltd | Administrative & support | 2019 |
| Hannah Newcombe Design Ltd | Professional & scientific | 2025 |
| Hanson-Gittens Property Ltd | Households | 2021 |
| Hanworth Homes Limited | Real estate | 2010 |
| Happy Ashley Limited | Wholesale & retail | 2019 |
| Happy Pizzas HR Trading AS Amore Pizzeria Ltd | Hospitality | 2023 |
| Happydashery Limited | Wholesale & retail | 2015 |
| Haptec Systems Limited | Manufacturing | 2010 |
| Harborne Manor Management Company Limited | Households | 2019 |
| Hardings (Stewkley) Limited | Education | 2017 |
| Hardy Elevations Limited | Construction | 2019 |
| Harisonhogg Ltd | Information & communication | 2023 |
| Harkstem Limited | Real estate | 1998 |
| Harlequin School of Gymnastics | Arts & recreation | 2001 |
| Harmill Systems Limited | Construction | 1990 |
| Harmony Acupuncture Ltd | Health & social care | 2023 |
| Harmsworth Real Estate Limited | Real estate | 2023 |
| Harpenden Tutors Limited | Education | 2010 |
| Harriott S & E Limited | Construction | 2014 |
| Harris Campervans Ltd | Wholesale & retail | 2024 |
| Harris Renovations Ltd | Construction | 2018 |
| Harveycombe Limited | Hospitality | 2010 |
| Harveycombe Mews Management Company Limited | Hospitality | 1993 |
| Haslam Massey Consulting Limited | Information & communication | 2010 |
| Haslewood Homes Ltd | Real estate | 2025 |
| Hastings Roofing Ltd | Construction | 2020 |
| Hatched.Co.Uk Ltd | Extraterritorial | 2007 |
| Hatchedepc.Co.Uk Limited | Extraterritorial | 2011 |
| Haul Britannia Limited | Transport & logistics | 2025 |
| Haus of Hounds Ltd | Manufacturing | 2025 |
| Hause of Retail Limited | Wholesale & retail | 2024 |
| Hawkhill Management Company Limited | Households | 2024 |
| Hawkins Kitchens and Bathrooms Limited | Construction | 2011 |
| Haycock Limited | Information & communication | 2024 |
| Haynes Village Hall Trading Limited | Hospitality | 1992 |
| Hazlewood Plant Sales Ltd | Wholesale & retail | 2021 |
| HBB Construction Limited | Construction | 2020 |
| HBC Real Estate Limited | Real estate | 2025 |
| HC Infrastructure and Energy Services Limited | Professional & scientific | 2026 |
| Healdan Capital Limited | Real estate | 2018 |
| Healdan Estates Ltd | Construction | 2018 |
| Healdan Limited | Real estate | 2018 |
| Health Data Xpert Limited | Information & communication | 2025 |
| Healthisgolden Limited | Extraterritorial | 2023 |
| Hearmenow.Ai Ltd | Information & communication | 2025 |
| Heart-Centred Leaders Limited | Professional & scientific | 2020 |
| Heath Renovations Ltd | Manufacturing | 2024 |
| Heathland Accountancy Limited | Professional & scientific | 2022 |