| Hennagise Limited | Arts & recreation | 2025 |
| Hennelly Properties Ltd | Real estate | 2016 |
| Henram Cleaning Services Ltd | Administrative & support | 2017 |
| Henry Bailey Limited | Extraterritorial | 2009 |
| Henry Infrastructure Ltd | Construction | 2016 |
| Henryway Limited | Health & social care | 2025 |
| Henzas Products Ltd | Wholesale & retail | 2025 |
| Hepta's Ltd | Information & communication | 2025 |
| Her-True-Modesty Ltd | Wholesale & retail | 2025 |
| HERE2CLEAN Herts & Beds Ltd | Other services | 2024 |
| Hereafter Homes Ltd | Construction | 2022 |
| Heritage Associates CIC | Education | 2023 |
| Heritage Blueprint Limited | Professional & scientific | 2025 |
| Heritage Building and Maintenance Limited | Construction | 2004 |
| Heritage FX Ltd | Transport & logistics | 2022 |
| Heritage Oak Property Group Ltd | Real estate | 2026 |
| Heritage Properties (Herts & Beds) Limited | Real estate | 2024 |
| Heritage Woven Limited | Wholesale & retail | 2025 |
| Hermitage 12 Limited | Real estate | 2022 |
| Hermz Window Cleaning & Building Maintenance Ltd | Administrative & support | 2026 |
| Hero K9 Ltd | Administrative & support | 2025 |
| Hertford Airport Taxis Limited | Transport & logistics | 2016 |
| Hertford Contracts Ltd | Construction | 2017 |
| Hertford North Station Taxis Limited | Transport & logistics | 2016 |
| Hertfordshire Chest Limited | Health & social care | 2017 |
| Hertfordshire Home Services Ltd | Construction | 2019 |
| Hertfordshire Microlight Club Ltd | Arts & recreation | 2018 |
| Hertfordshire Park Homes Ltd | Construction | 2022 |
| Hertfordshire Property Prosperity Ltd | Real estate | 2019 |
| Herts and Glos Investments Limited | Real estate | 2007 |
| Herts Detailz Limited | Wholesale & retail | 2024 |
| Herts Handling Training Limited | Health & social care | 2010 |
| Herts Haulage Limited | Transport & logistics | 2021 |
| Herts Horizon Ltd | Transport & logistics | 2025 |
| Herts Planning and Development Ltd | Construction | 2020 |
| Herts Premier Properties Limited | Real estate | 2024 |
| Herts Tool & Plant Hire Limited | Administrative & support | 2021 |
| Hesperis Technology Limited | Extraterritorial | 2003 |
| Hestia Heritage Limited | Other services | 2017 |
| Hetty Consulting Ltd | Information & communication | 2010 |
| Hetz Holdings Ltd | Financial services | 2021 |
| Hewelt Ltd | Transport & logistics | 2024 |
| Hewkin TM Ltd | Construction | 2025 |
| Hewlett Auto Services Limited | | 1984 |
| Hewlett Road Development Limited | Construction | 2025 |
| Hexagonal Engineering Ltd | Construction | 2005 |
| Hexagonal London Limited | Construction | 2015 |
| Heydon Pierre Limited | Construction | 2012 |
| Heyven Homes Ltd | Wholesale & retail | 2025 |
| HF09 Ltd | Real estate | 2025 |
| HFC Security Ltd | Wholesale & retail | 2024 |
| HFI Events Ltd | Professional & scientific | 2026 |
| HGV1 Ltd | Transport & logistics | 2021 |
| HH & Sons Ltd | Hospitality | 2023 |
| HH Online Limited | Wholesale & retail | 2025 |
| HH Optical Services Ltd | Health & social care | 2025 |
| HH Protection Ltd | Administrative & support | 2016 |
| Hh-Tech Ltd | Wholesale & retail | 2022 |
| Hhh&Co Ltd | Wholesale & retail | 2025 |
| Hhhh Properties UK Ltd | Transport & logistics | 2025 |
| HHI Ahmed Limited | Real estate | 2017 |
| HHI United Limited | Administrative & support | 2023 |
| HHK Property Maintenance Limited | Construction | 2020 |
| Hhku Ltd | Construction | 2025 |
| HHM London Limited | Real estate | 2023 |
| HI & MWK Properties Limited | Real estate | 2020 |
| Hi-Tech & Engineering Limited | Construction | 2018 |
| Hibah & Bros Properties Ltd | Real estate | 2023 |
| Hibba Investment Group Ltd | Real estate | 2019 |
| Hibba Take Away Ltd | Hospitality | 2019 |
| Hidaaya Dawathe Islam Ltd | Health & social care | 2024 |
| Hidden Rose Limited | Real estate | 2019 |
| Hidden Worlds Ltd | Information & communication | 2020 |
| Hidingplace Ltd | Health & social care | 2024 |
| High Flying Food Limited | Hospitality | 2011 |
| High Rize Solutions Ltd | Wholesale & retail | 2019 |
| High Secure Services Limited | Financial services | 2023 |
| High Spec Autos Ltd | Wholesale & retail | 2023 |
| High Town Motor Services Ltd | Wholesale & retail | 2026 |
| High-End Howlers Limited | Wholesale & retail | 2025 |
| Highbury Cash & Carry Ltd | Wholesale & retail | 2023 |
| Highbury Groceries Limited | Wholesale & retail | 2026 |
| Higher Flow Ltd | Arts & recreation | 2025 |
| Higher Values Limited | Real estate | 2025 |
| Highfell Digital Limited | Information & communication | 2025 |
| Highness Contracting and Trading UK Ltd | Wholesale & retail | 2025 |
| Hightown Cafe Ltd | Hospitality | 2025 |
| Hightown Food and Wine Ltd | Wholesale & retail | 2014 |
| Hightown Tone Ltd | Other services | 2025 |
| Hightown Transport Services Ltd | Transport & logistics | 2024 |
| Highview Marketing Limited | Information & communication | 2020 |
| Highview Personnel Ltd | Health & social care | 2016 |
| Highview Trading Limited | Other services | 2022 |
| Highway One Services Limited | Transport & logistics | 2019 |
| Highworth Consulting Ltd | Professional & scientific | 2014 |
| HIH Logistics Ltd | Transport & logistics | 2025 |
| Hijabeaze Limited | Wholesale & retail | 2024 |
| Hijama Clinic Limited | Health & social care | 2015 |
| Hijra Logistics Ltd | Transport & logistics | 2020 |
| Hikl Limited | Construction | 2014 |