| HE Design & Build Ltd | Construction | 2017 |
| Health Boost Clinic Ltd | Other services | 2024 |
| Health Forecast Limited | Health & social care | 2016 |
| Health Venture Partners Ltd | Professional & scientific | 2024 |
| Healthcare Resource Company Ltd | Health & social care | 2020 |
| Healthpro World Ltd | Professional & scientific | 2016 |
| Healthy Working People Limited | Professional & scientific | 2008 |
| Healthywork Limited | Health & social care | 2001 |
| Heard Upstream Consulting Ltd | Mining & quarrying | 2017 |
| Hearts Development Limited | Arts & recreation | 2026 |
| HEARTS4MEN Ltd | Hospitality | 2024 |
| Heath Hair Company Limited | Other services | 2009 |
| Heath Plumbing Limited | Construction | 2004 |
| Heathdean Project Management Limited | Professional & scientific | 2024 |
| Heatherwood Management Company Limited | Households | 1985 |
| Heathlands (Buckley) Management Company Limited | Households | 2009 |
| Heathway (Tilehurst) Management Company Limited | Households | 2009 |
| Heatville Ltd | Wholesale & retail | 2023 |
| Heavenly Kids Childcare Limited | Health & social care | 2016 |
| Heavy Wind Media UK Ltd | Information & communication | 2010 |
| Heccom Limited | Wholesale & retail | 2019 |
| Hedera Gardens Resident Management Company Limited | Households | 2019 |
| Hedge Busters Ltd | Transport & logistics | 2026 |
| Hedgehog Films Limited | Arts & recreation | 2024 |
| Hedgerow Services Limited | Administrative & support | 2005 |
| Hedgerows Management Company (Woore) Limited | Real estate | 2018 |
| Heffley Ltd | Professional & scientific | 2022 |
| Heidelberg Engineering Limited | Professional & scientific | 2011 |
| HEL Group Holdings Limited | Professional & scientific | 2017 |
| HEL Limited | Professional & scientific | 1987 |
| Helichrysum Italicum Ltd | Manufacturing | 2022 |
| Helios Park Management Company Limited | Households | 2018 |
| Helium Animation Limited | Arts & recreation | 2018 |
| Hello Blondie Ltd | Hospitality | 2020 |
| Helm Gardens (Natland) Management Company Limited | Households | 2017 |
| Helrai Ltd | Other services | 2020 |
| Helstonhounds Limited | Professional & scientific | 2013 |
| Hemberton Advisers Limited | Professional & scientific | 2025 |
| Hemel Accountants Limited | Professional & scientific | 2023 |
| Hemel Airport Chauffeurs Limited | Transport & logistics | 2023 |
| Hemel Builders Limited | Construction | 2025 |
| Hemel Car Sales Ltd | Wholesale & retail | 2019 |
| Hemel Cars & Taxis Ltd | Transport & logistics | 2014 |
| Hemel Carz Ltd | Wholesale & retail | 2025 |
| Hemel Consultants Ltd | Other services | 2016 |
| Hemel Cottage Ltd | Professional & scientific | 2020 |
| Hemel Developments Limited | Real estate | 2003 |
| Hemel DRY Cleaners Limited | Other services | 2020 |
| Hemel Eggs Limited | Wholesale & retail | 2001 |
| Hemel Executive Cars Limited | Transport & logistics | 2021 |
| Hemel Express Ltd | Wholesale & retail | 2022 |
| Hemel Food Enterprise Ltd | Hospitality | 2024 |
| Hemel Glass Ltd | Manufacturing | 2009 |
| Hemel Hempstead Catering Ltd | Hospitality | 2023 |
| Hemel Hempstead Community Church | Other services | 2004 |
| Hemel Hempstead Day Centre Limited(The) | Health & social care | 1976 |
| Hemel Hempstead Tailors Limited | Wholesale & retail | 2023 |
| Hemel Hempstead Taxis Ltd | Transport & logistics | 2021 |
| Hemel Home and Garden Services Limited | Administrative & support | 2012 |
| Hemel Indoor Tennis Centre Limited | Arts & recreation | 1992 |
| Hemel International Consultancy Limited | Professional & scientific | 2010 |
| Hemel IT & Graphic Ltd | Information & communication | 2025 |
| Hemel Motors Limited | Wholesale & retail | 2018 |
| Hemel Physio Limited | Health & social care | 2025 |
| Hemel Pizza Limited | Hospitality | 2024 |
| Hemel Plus Limited | Hospitality | 2025 |
| Hemel Snowcentre Limited | Other services | 2007 |
| Hemel Storm Basketball Community Interest Company | Arts & recreation | 2023 |
| Hemel Tailoring Limited | Manufacturing | 2025 |
| Hemel Taxis 247 Ltd | Transport & logistics | 2019 |
| Hemel Thai Express Ltd | Hospitality | 2016 |
| Hemel Trade & D.I.Y. Supplies Limited | Wholesale & retail | 2007 |
| Hemel Travels Ltd | Transport & logistics | 2025 |
| Hemel Wargamers Limited | Wholesale & retail | 2025 |
| Hemel Web Design Limited | Information & communication | 2021 |
| Hemelbutchers Limited | Wholesale & retail | 2020 |
| Hemelhempstead Food and Wine Ltd | Wholesale & retail | 2012 |
| Hemsure Limited | Construction | 2024 |
| Henderson Park (Thorpe LE Soken) Management Company Limited | Households | 2017 |
| Henkel Bidco Ltd. | Financial services | 2025 |
| Henkel Industrial Adhesives Ltd | Manufacturing | 2008 |
| Henkel Limited | Professional & scientific | 1926 |
| Henkel UK Operations Limited | Manufacturing | 1999 |
| Henny Services Ltd | Health & social care | 2018 |
| Henry Building Ltd | Construction | 2022 |
| Henry Contractors Ltd | Construction | 2026 |
| Henry's Electrical Services Limited | Other services | 2018 |
| Hepburn Delaney Ltd | Professional & scientific | 2013 |
| Herdwick Holiday Park Limited | Arts & recreation | 2026 |
| Herin Limited | Wholesale & retail | 2018 |
| Heritage Floral Co. Limited | Wholesale & retail | 2025 |
| Heritage Gate Resident Management Company Limited | Households | 2007 |
| Heritage HPR Ltd | Construction | 2019 |
| Heritage Management Limited | Households | 2004 |
| Herkules Ltd | Transport & logistics | 2018 |
| Hermanus Properties Limited | Construction | 2011 |
| Heron Business Park Limited | Real estate | 2006 |
| Hertfordshire Car Services Ltd | Transport & logistics | 2024 |
| Hertfordshire Doors Limited | Construction | 2022 |
| Hertfordshire Joinery Ltd | Construction | 2014 |