| Goodwin Capital Group Ltd | Real estate | 2025 |
| Goodwin Leisure Limited | Wholesale & retail | 1996 |
| Gowland Securities Limited | Real estate | 2025 |
| Goxplorers Ltd | Administrative & support | 2026 |
| GPA Global UK Limited | Professional & scientific | 1996 |
| Graeme K Whippy Ltd | Information & communication | 2007 |
| Grainger Motor Group Ltd | Financial services | 2022 |
| Grand Park Homes Ltd | Health & social care | 2022 |
| Grannatech Limited | Wholesale & retail | 2000 |
| Grant DAQ Solutions Limited | Manufacturing | 2015 |
| Grant Instruments (Cambridge) Limited | Manufacturing | 1960 |
| Granta IP Services Ltd | Professional & scientific | 2025 |
| Grayling Investments Ltd | Real estate | 2020 |
| Great North Partnership Ltd | Real estate | 2021 |
| Green Eco Solar Solutions Ltd | Construction | 2012 |
| Green Heat Coop Ltd | Professional & scientific | 2022 |
| Green Rabbit Developments Limited | Real estate | 2012 |
| Greenform Construction Services Limited | Administrative & support | 2004 |
| Greenheart Timber Frame Limited | Construction | 2010 |
| Greenstone Consulting Limited | Real estate | 2014 |
| Greenstone Refrigeration Services Limited | Construction | 1999 |
| Greentech Limited | Manufacturing | 2002 |
| Grimley Consulting Ltd | Professional & scientific | 2022 |
| Groundtrax Systems Limited | Construction | 2011 |
| Groves Marchant Limited | Wholesale & retail | 2000 |
| Grundy & Co. Ltd | Real estate | 2010 |
| GS Legacy Investments Limited | Real estate | 2025 |
| GS4 Interiors Limited | Construction | 2011 |
| GSL International Limited | Wholesale & retail | 2025 |
| Guest Guru Ltd | Information & communication | 2018 |
| Guilden Project Consultancy Limited | Professional & scientific | 2023 |
| Gyro Flying School Limited | Education | 2018 |
| H & E Plastering Limited | Construction | 2018 |
| H S Business System Ltd | Other services | 2023 |
| H S Property Consulting Ltd | Real estate | 2010 |
| H.V. Richmond Limited | Transport & logistics | 1978 |
| H2A Partners Ltd | Wholesale & retail | 2024 |
| H2O GAS, Heating & Plumbing Services Limited | Construction | 2003 |
| Hair by Huma Ltd | Other services | 2018 |
| Haitch & Joes Limited | Other services | 2019 |
| Halcyons Heart Films Limited | Information & communication | 2006 |
| Hall Lane Barns Management Company Limited | Households | 2019 |
| Halls Hospitality Ltd | Real estate | 2013 |
| Hamry Construction Consultants Limited | Construction | 2010 |
| Hamstead Soundworks Limited | Manufacturing | 2014 |
| Handscombe Limited | Construction | 2003 |
| Handy Professional Services Ltd | Administrative & support | 2018 |
| Hanson Diamond Drilling Ltd | Construction | 2021 |
| Hanson Lettings Limited | Real estate | 2024 |
| Hanson Services Holding Ltd | Financial services | 2021 |
| Hanson Services Limited | Construction | 2008 |
| Happy Self Storage Ltd | Real estate | 2017 |
| Hard Jelly Ltd | Wholesale & retail | 2022 |
| Hardcastle Burton Financial Limited | Financial services | 2013 |
| Hardcastle Burton Limited | Professional & scientific | 1999 |
| Hardcastle Burton LLP | | 2008 |
| Hardy Landscapes Limited | Administrative & support | 2016 |
| Harmes Securities Limited | Administrative & support | 2021 |
| Harmonisation Limited | Administrative & support | 2012 |
| Harris Electrical Design and Installation Limited | Construction | 2023 |
| Harrison Construction & Property Services Ltd | Construction | 2026 |
| Harrison Life Sciences Group Limited | Professional & scientific | 2013 |
| Harvalf Homes Ltd | Real estate | 2025 |
| Harvey-Benns Publishing Limited | Information & communication | 2023 |
| Hasu Properties Limited | Real estate | 2020 |
| Hasu Racing Limited | Wholesale & retail | 2019 |
| HAT Community Foundation | Information & communication | 2015 |
| Hatter's Farm Ltd | Wholesale & retail | 2021 |
| Hatters Court Management Limited | Households | 1998 |
| Haus of Hyde Limited | Professional & scientific | 2015 |
| Hawthorn Consultancy Ltd | Professional & scientific | 2014 |
| Hawthorn Ecology Ltd | Professional & scientific | 2026 |
| Hawthorn Ventures Limited | Real estate | 1997 |
| Hawthorne Goode Limited | Administrative & support | 2017 |
| Hayleys Property Limited | Real estate | 2019 |
| Haynes Outside Catering Ltd | Hospitality | 2021 |
| Hazel Court (Loughton) RTM Company Ltd | Households | 2015 |
| Hazelnuthill Properties Ltd | Financial services | 2009 |
| Hazelvale Properties Limited | Real estate | 1988 |
| HC Stanley Limited | Financial services | 2025 |
| HCD Carbon Ltd | Manufacturing | 2025 |
| Headland Amenity Limited | Wholesale & retail | 1993 |
| Headworks Think Space Ltd | Real estate | 2026 |
| Health Matters Technology Limited | Health & social care | 2014 |
| Healthwise Catalyst Limited | Health & social care | 2021 |
| Heasell Electromechanical Services Ltd | Other services | 2001 |
| Heathfield Consultants Ltd | Other services | 2020 |
| Heathfields Residents Association Limited | Households | 1983 |
| Hedderwick Consulting Limited | Professional & scientific | 2024 |
| Hedgepig Spirits Ltd | Manufacturing | 2024 |
| Helen Aston Limited | Professional & scientific | 2026 |
| Hellbound Heart Ltd | Arts & recreation | 2024 |
| Helve Ventures Ltd | Professional & scientific | 2026 |
| Helvetica Capital Limited | Real estate | 2019 |
| Henderson Asset Protection UK Limited | Professional & scientific | 2004 |
| Henderson Risk Limited | Administrative & support | 2002 |
| Henley Court (Freeholders) Limited | Households | 2002 |
| Henrick Hairdressing Ltd | Other services | 2005 |
| Heraldic Silver Limited | Wholesale & retail | 2009 |
| Hertfordshire Motors Limited | Wholesale & retail | 2017 |