| Hatfield Best Kebab Wrap Limited | Hospitality | 2024 |
| Hatfield Community Free School | Education | 2011 |
| Hatfield Cultural Connection CIC | Wholesale & retail | 2025 |
| Hatfield Dessert Corner Ltd | Hospitality | 2023 |
| Hatfield House Chamber Music Festival | Arts & recreation | 2012 |
| Hatfield Launderette &DRY Cleaners Ltd | Other services | 2021 |
| Hatfield Lettings Limited | Real estate | 2006 |
| Hatfield Local Ltd | Wholesale & retail | 2026 |
| Hatfield MAN and Van Services Limited | Administrative & support | 2024 |
| Hatfield Market Place Consortium Limited | Other services | 1989 |
| Hatfield Rise Launderette Ltd | Other services | 2022 |
| Hatfield Spice Ltd | Hospitality | 2019 |
| Hatfield Trading Limited | Real estate | 2006 |
| Hatfieldpizza Ltd | Hospitality | 2025 |
| Hatfieldtech Limited | Wholesale & retail | 2025 |
| Hatiz Cafe Ltd | Hospitality | 2018 |
| Hausmate Ltd | Real estate | 2025 |
| Havenvale Properties Ltd | Construction | 2025 |
| Haverhill Car Xchange Ltd | Wholesale & retail | 2010 |
| Havis Builders Limited | Real estate | 1964 |
| HAY on WYE Investments | Administrative & support | 2018 |
| Hayat Global Ltd | Wholesale & retail | 2025 |
| Hayatz Private Limited | Hospitality | 2024 |
| Hayley Pomfrett Limited | Administrative & support | 2012 |
| HAZ Building Accessories Ltd | Wholesale & retail | 2025 |
| HAZ Metal Fixing Systems UK Limited | Wholesale & retail | 2016 |
| Hazel Food & Wine Ltd | Wholesale & retail | 2018 |
| Hazelgrove Manor Care Limited | Health & social care | 2024 |
| HB Builders Ltd | Construction | 2017 |
| HBB Electrical Services Ltd | Construction | 2023 |
| HBD Surveyors Ltd | Professional & scientific | 2013 |
| Hbma Ltd | Wholesale & retail | 2025 |
| Hdop Ltd | Hospitality | 2019 |
| He(A)Rts DOC Ltd | Education | 2015 |
| Heal Conscious Ltd | Health & social care | 2026 |
| Healion Pharma Ltd | Manufacturing | 2025 |
| Health & Fitness Tea Limited | Wholesale & retail | 2016 |
| Healthcare Provision Limited | Health & social care | 2012 |
| Healthibites Ltd | Wholesale & retail | 2024 |
| Heart Community Services Ltd | Transport & logistics | 2026 |
| Hearth Hoof Limited | Wholesale & retail | 2025 |
| Heartsathome Ltd | Health & social care | 2020 |
| Heath & Co Executive Services Ltd | Administrative & support | 2025 |
| Hecc Cricket School Limited | Arts & recreation | 2015 |
| Heed to Care Ltd | Administrative & support | 2023 |
| Hefty Films Limited | Information & communication | 2024 |
| Helix 360 Facilities Ltd | Administrative & support | 2026 |
| Helm Rigging Services Ltd | Construction | 2019 |
| Helping Market Limited | Information & communication | 2020 |
| Henneberry Homes Ltd | Construction | 2021 |
| Henry James Outsourcing Limited | Information & communication | 2008 |
| Henry James Property Investments Limited | Real estate | 2016 |
| Henry Joseph LLP | | 2022 |
| HER Connect Hub Limited | Administrative & support | 2021 |
| Herisha Limited | Real estate | 2025 |
| Heritage Brides Limited | Wholesale & retail | 2017 |
| Heritage Landscapes (Herts) Ltd | Administrative & support | 2026 |
| Heritage Television Limited | Information & communication | 2012 |
| Hero PHS Ltd | Construction | 2019 |
| Hertford Bar Services Ltd | Hospitality | 2024 |
| Hertford Leasing Limited | Wholesale & retail | 1999 |
| Hertfordshire Art Therapy Ltd | Health & social care | 2019 |
| Hertfordshire Community Foundation | Other services | 2013 |
| Hertfordshire Compliance Services Ltd | Transport & logistics | 2023 |
| Hertfordshire Cycle Repairs Ltd | Wholesale & retail | 2023 |
| Hertfordshire Heating Limited | Extraterritorial | 2016 |
| Hertfordshire Premier Travel Ltd | Transport & logistics | 2024 |
| Hertfordshire Telugu Association | Education | 2017 |
| Hertingfordbury Agricultural Ltd | Wholesale & retail | 2026 |
| Hertingfordbury Developments Limited | Construction | 2023 |
| Hertingfordbury Investments Limited | Real estate | 1995 |
| Herts Appliances Service Ltd | Manufacturing | 2022 |
| Herts Digiverse Ltd | Information & communication | 2024 |
| Herts Drone Solution Ltd | Professional & scientific | 2019 |
| Herts Engineering and Trading Limited | Wholesale & retail | 2016 |
| Herts Fabrics Limited | Wholesale & retail | 2026 |
| Herts Hypnosis & Psychotherapy Limited | Professional & scientific | 2010 |
| Herts Mandarin Ltd | Education | 2023 |
| Herts on Point Services Ltd | Health & social care | 2013 |
| Herts Property Inventories & Inspections Limited | Administrative & support | 2019 |
| Herts Services Solution Ltd | Information & communication | 2024 |
| Herts Utopia Limited | Real estate | 2016 |
| Herts Young Homeless Group | Health & social care | 1998 |
| Herts, Beds & Bucks Horsebox Hire Ltd | Administrative & support | 2020 |
| Hertscapes Ltd | Administrative & support | 2025 |
| Hertsyouth Ltd | Other services | 2025 |
| Hexagon Projects Ltd | Construction | 2012 |
| Hexham Marketing Limited | Information & communication | 2022 |
| HEY YOU Guys Limited | Construction | 2022 |
| HEY YOU Guys SPV Limited | Real estate | 2024 |
| Heyns Commercials Ltd | Manufacturing | 2019 |
| HG Pharma Limited | Health & social care | 2019 |
| HGT Management Services Ltd | Professional & scientific | 2024 |
| Hidden Door Productions Limited | Information & communication | 2015 |
| High Spirits Property Limited | Real estate | 2016 |
| High Yoga Ltd | Education | 2020 |
| Highbridge Essential Services Ltd | Administrative & support | 2025 |
| Highfield London Limited | Construction | 2010 |
| Highgrade Development Solutions Limited | Construction | 2005 |
| Hightech Composite Ltd | Manufacturing | 2018 |