| Helg Ltd | Hospitality | 2022 |
| Helgoiq Limited | Information & communication | 2026 |
| Helix Healthcare Ltd | Health & social care | 2020 |
| Helix PPM Limited | Professional & scientific | 2013 |
| Hellichem Limited | Wholesale & retail | 2014 |
| Helpfulhandsbsl Ltd | Administrative & support | 2024 |
| Helpmyhouse Ltd | Other services | 2024 |
| HEM Installation Systems Ltd | Construction | 2003 |
| Henderson Windows Limited | Construction | 2016 |
| Heneom Group Ltd | Professional & scientific | 2024 |
| Hennah Rigging Ltd | Construction | 2015 |
| Hensar Holdings Limited | Real estate | 2023 |
| Hepburn Darby Cabling Solutions Ltd | Construction | 2022 |
| Hepburn Family Investments (UK) Limited | Financial services | 2026 |
| Herbert & Ball Holdings Limited | Other services | 2018 |
| Herbotech Systems Ltd | Information & communication | 2024 |
| Herd Consultancy Limited | Professional & scientific | 2025 |
| Herd International Group Ltd | Information & communication | 2024 |
| Herd International Ltd | Information & communication | 2022 |
| Here for Business Limited | Other services | 2024 |
| Heriitage Care Ltd | Administrative & support | 2019 |
| Heriitage World Ltd | Real estate | 2025 |
| Heritage Commercial Interiors Ltd | Construction | 2026 |
| Heritage Gardens (Great Offley) Management Company Limited | Households | 2014 |
| Heritage Holdings Management Limited | Financial services | 2024 |
| Heritage Maintenance Services Ltd | Construction | 2026 |
| Heritage-Letts Ltd | Real estate | 2017 |
| Hertford Holdings Limited | Real estate | 2015 |
| Hertfordshire Building & Maintenance Limited | Construction | 2011 |
| Hertfordshire Cctv Partnership Ltd | Information & communication | 2014 |
| Hertfordshire Complete Construction Services Limited | Construction | 2020 |
| Hertfordshire Cricket Limited | Arts & recreation | 2008 |
| Hertfordshire Driveways Limited | Construction | 2004 |
| Hertfordshire Electrical Company Limited | Construction | 2025 |
| Hertfordshire Equality Council | Information & communication | 2011 |
| Hertfordshire Fencing & Maintenance Limited | Construction | 1999 |
| Hertfordshire Grab Service Ltd | Construction | 2021 |
| Hertfordshire Holdings Limited | Real estate | 2015 |
| Hertfordshire Interiors Limited | Construction | 2013 |
| Hertfordshire Woodworks Limited | Wholesale & retail | 2009 |
| Herts A1 Ltd | Other services | 2022 |
| Herts Air Conditioning Services Ltd | Administrative & support | 2019 |
| Herts and Beds Vascular Service Ltd | Health & social care | 2020 |
| Herts Carpentry Limited | Construction | 2014 |
| Herts Deer Ltd | Transport & logistics | 2025 |
| Herts Design and Creative Services Ltd | Professional & scientific | 2022 |
| Herts Dive Club (H D C) Ltd | Arts & recreation | 2025 |
| Herts Embroidery Ltd | Professional & scientific | 2022 |
| Herts Fitout Ltd | Construction | 2023 |
| Herts Food Services Ltd | Wholesale & retail | 2026 |
| Herts for Learning Limited | Education | 2013 |
| Herts Handymen Ltd | Construction | 2026 |
| Herts Independent Social Support Limited | Health & social care | 2014 |
| Herts Interactive Limited | Professional & scientific | 2016 |
| Herts Living Limited | Construction | 2017 |
| Herts Maintain and Build Ltd | Construction | 2023 |
| Herts Party Bags Limited | Wholesale & retail | 2016 |
| Herts Renewable Services Ltd | Construction | 2022 |
| Herts Roofing Ltd | Construction | 2019 |
| Herts Skiphire Limited | Water & waste | 2012 |
| Herts Sparks Ltd | Construction | 2025 |
| Herts Ultrasound Scan Ltd | Health & social care | 2026 |
| Herts Urgent Dental Care (OUT of Hours) Limited | Health & social care | 2008 |
| Herts Waste Removal Ltd | Water & waste | 2025 |
| Hertshawk Construction Ltd | Construction | 2023 |
| Hertz Construction Ltd | Construction | 2024 |
| HEX Global Limited | Real estate | 2024 |
| Hexnet Services Ltd | Information & communication | 2018 |
| Heyward Group Limited | Professional & scientific | 2015 |
| HF Beauty Bar Ltd | Other services | 2025 |
| HGG Holdings Limited | Financial services | 2024 |
| HH Trading Enterprises Limited | Information & communication | 2020 |
| HI Point Autos Ltd | Wholesale & retail | 2013 |
| HI- Tech Ultrasound Limited | Professional & scientific | 2024 |
| Hi-Vu Ltd | Wholesale & retail | 2013 |
| Hicare Healthcare Ltd | Health & social care | 2023 |
| Hicksonscott Plumbing Services Limited | Construction | 2010 |
| Hide and Seek Media Limited | Information & communication | 2019 |
| Hifi Industrial Film Limited | Manufacturing | 1984 |
| High HAT Media Ltd | Information & communication | 2013 |
| High Hope Clothing Limited | Extraterritorial | 2018 |
| High Street Holiday Limited | Other services | 2025 |
| Highfield CNC Engineering Limited | Manufacturing | 2001 |
| Highview Maintenance Services Limited | Administrative & support | 2016 |
| Hilife Development Limited | Professional & scientific | 2008 |
| Hillcrest Accountancy Ltd | Professional & scientific | 2014 |
| Hills Cooper Performance Limited | Administrative & support | 2025 |
| Hillson London Limited | Real estate | 2016 |
| Hilltop Walk (Watton) Limited | Construction | 2017 |
| Hilsen Limited | Construction | 2025 |
| Hima Construction Ltd | Construction | 2021 |
| Hingston Roofing Limited | Construction | 1997 |
| Hinterland Limited | Education | 1983 |
| HIP Maintenance Ltd | Water & waste | 2021 |
| Hire ARC Ltd | Administrative & support | 2025 |
| Hirons Consulting Services Limited | Professional & scientific | 2018 |
| Hitchin Blinds Limited | Wholesale & retail | 2022 |
| Hive EHK Limited | Professional & scientific | 2020 |
| Hive Support Solutions Limited | Other services | 2018 |
| Hjlc Holdings Limited | Administrative & support | 2022 |