| Green Direction Ltd | Professional & scientific | 2024 |
| Green Infrastructure Consultancy Ltd | Professional & scientific | 2010 |
| Green Umbrella Marketing Limited | Information & communication | 2015 |
| Greenacres Capital Limited | Financial services | 2020 |
| Gregory Homes Interiors Ltd | Construction | 2026 |
| Grelec International Limited | Professional & scientific | 2016 |
| Grenadier Trees and Grounds Ltd | Administrative & support | 2026 |
| Greyhound Estates Limited | Households | 2011 |
| Gribex Trans Ltd | Transport & logistics | 2025 |
| Grindlay Management Services Limited | Wholesale & retail | 1997 |
| Grindmax Company Limited | Professional & scientific | 2018 |
| Groundcore Limited | Construction | 2016 |
| Groves Builders Limited | Construction | 2003 |
| Growth Guru - Business Planning Ltd | Administrative & support | 2022 |
| Grzegorz Hamala Ltd | Wholesale & retail | 2019 |
| GSI Equipment Limited | Administrative & support | 1989 |
| GTI Power Generation Ltd | Manufacturing | 1985 |
| GTJ Lube OIL Co., Limited | Professional & scientific | 2019 |
| GTN Merchants Ltd | Manufacturing | 2017 |
| Guanqiang Trading Co., Limited | Professional & scientific | 2023 |
| Guest-Gallop Int'L Capital Management Group Company Limited | Professional & scientific | 2006 |
| Guidebook Limited | Information & communication | 2014 |
| Gutmind Alliance Limited | Health & social care | 2026 |
| GW Design & Modelling Limited | Professional & scientific | 2022 |
| GWT Services Ltd | Professional & scientific | 2022 |
| Gymflex Daventry Limited | Arts & recreation | 2026 |
| Gymflex Protein Limited | Wholesale & retail | 2026 |
| GYO Energy Ltd | Construction | 2014 |
| H & H (Midlands) Limited | Real estate | 2017 |
| H.E.S. Sales Limited | Wholesale & retail | 2006 |
| Halation Limited | Information & communication | 2026 |
| Hambleside Danelaw Limited | Manufacturing | 1976 |
| Hammang Trans Ltd | Transport & logistics | 2019 |
| Hammond Town Planning Ltd | Professional & scientific | 2021 |
| Hamp Machinery Services Limited | Professional & scientific | 2010 |
| Handyman JC Ltd | Professional & scientific | 2018 |
| Hankook Tyre U.K. Limited | Manufacturing | 1993 |
| HANNA2018 Ltd | Transport & logistics | 2018 |
| Happenstance@Zepic C.I.C. | Wholesale & retail | 2026 |
| Happy Kidz Day Care Limited | Health & social care | 2019 |
| Haras Building Contractors Ltd | Construction | 2021 |
| Harley Equestrian Limited | Wholesale & retail | 2008 |
| Harris & Co. Property Ltd | Real estate | 2025 |
| Harry Smith Capital Limited | Financial services | 2025 |
| Hasco-Internorm Limited | Wholesale & retail | 1977 |
| Hatton Solicitors Limited | Professional & scientific | 2019 |
| Haydens Haulage Ltd | Transport & logistics | 2016 |
| Hayfields Dog Hotel Limited | Agriculture & fishing | 2012 |
| Haynes and Sons (Daventry) Limited | Construction | 1950 |
| Hazexperts Limited | Water & waste | 2019 |
| Hazma Healthcare Limited | Health & social care | 2023 |
| HCF (EDW) Limited | Financial services | 2023 |
| HCF (Holdings) Limited | Financial services | 2025 |
| HCF (PGW) Ltd | Agriculture & fishing | 2021 |
| HCF Farms Limited | Agriculture & fishing | 2024 |
| HD Event Services Ltd | Administrative & support | 2023 |
| HDH Marketing Ltd | Professional & scientific | 2023 |
| Healey and Sons Building Limited | Construction | 2024 |
| Health Align Ltd | Extraterritorial | 2017 |
| Healtholozy UK Limited | Wholesale & retail | 2017 |
| Healthy Returns Consultancy Ltd | Professional & scientific | 2010 |
| Hear Sure Ltd | Health & social care | 2025 |
| Heart & Home Industries Ltd | Administrative & support | 2025 |
| Heart and Bloom Tribute Florals Ltd | Wholesale & retail | 2026 |
| Heartlands Physiotherapy Clinic Limited | Health & social care | 2007 |
| HELFINIAN3 Ltd | Agriculture & fishing | 2024 |
| Helixx Technologies UK Ltd | Information & communication | 2025 |
| Helixx UK Holdings Ltd | Financial services | 2025 |
| Hellidon Group Ltd | Information & communication | 2004 |
| Hellidon Solutions Limited | Hospitality | 2004 |
| Helpdesk & Training Group Ltd | Water & waste | 2022 |
| Herbie Investments Ltd | Financial services | 2025 |
| Herbiness Ltd | Wholesale & retail | 2019 |
| Heritages Consultants Ltd | Professional & scientific | 2023 |
| Herolift Material Handling Co., Limited | Professional & scientific | 2019 |
| Heron Contracts Ltd | Construction | 2026 |
| HHH Supplies Ltd | Wholesale & retail | 2017 |
| Hhrm Transport Ltd | Transport & logistics | 2023 |
| Hi-Force Group Holdings Ltd | Financial services | 2018 |
| Hi-Force Limited | Manufacturing | 2006 |
| Hibbert Admin Services Ltd | Administrative & support | 2021 |
| High Cross Farm Limited | Real estate | 2008 |
| High Tech International Industrial Limited | Professional & scientific | 2023 |
| Highcross Business Associates Ltd | Professional & scientific | 2006 |
| Highfields Homes Limited | Construction | 2020 |
| Hikfinds Limited | Wholesale & retail | 2025 |
| Hill Valley Signs Limited | Administrative & support | 2013 |
| Hillary Properties Limited | Real estate | 2015 |
| Himmat Properties Limited | Real estate | 2002 |
| Hinton Carpets Limited | Construction | 2014 |
| Hinton Manor Court Management Company Limited | Households | 1995 |
| Hinton Vehicle Services Ltd | Wholesale & retail | 2020 |
| HJ Trading Co., Ltd | Professional & scientific | 2023 |
| Holistic Business Consulting Limited | Professional & scientific | 2023 |
| Hollow Mountain Holdings Limited | Real estate | 2025 |
| Home Farm Events Ltd | Hospitality | 2014 |
| Honeyland Estate Agents Ltd | Real estate | 2026 |
| Honeyland Properties Ltd | Construction | 2025 |
| Honeysuckle Consulting Ltd | Professional & scientific | 2023 |
| Hood Road Store Limited | Wholesale & retail | 2019 |