| G D Construction (ST. Albans) Limited | Construction | 1995 |
| G D Construction Group Limited | Financial services | 2025 |
| G K Icon Academies Limited | Education | 2020 |
| G Mason Holdings Ltd | Education | 2023 |
| G Rigging and Lighting Ltd | Arts & recreation | 2011 |
| G Valentino Services Limited | Other services | 2023 |
| G&T Consulting Ltd | Information & communication | 2022 |
| G-Cloud UK Ltd | Wholesale & retail | 2014 |
| G.A.F Roofing & Building Ltd | Construction | 2026 |
| G.G.S. Compressors Limited | Construction | 1986 |
| G.I.S. Industrial Supply Co. Limited | Wholesale & retail | 1979 |
| G.J. Harper Limited | Wholesale & retail | 2003 |
| G4MES Ltd | Manufacturing | 2024 |
| GA Cooper Properties Limited | Real estate | 2016 |
| Gaam Consulting Limited | Professional & scientific | 2024 |
| Gabare Ltd | Real estate | 1998 |
| Gabel Investments Limited | Real estate | 2024 |
| Gabichar Enterprises Ltd. | Administrative & support | 2009 |
| Gabriel Chauffeur Hire Limited | Transport & logistics | 2022 |
| Gadget Planet Limited | Wholesale & retail | 2006 |
| Gadget Xpertz Limited | Wholesale & retail | 2026 |
| Gadgeteer Limited | Other services | 2014 |
| Gaia Earth Ltd | Agriculture & fishing | 2020 |
| Gainsborough Developments Limited | Real estate | 2016 |
| Gainsborough Road (Hayes) Residents Limited | Administrative & support | 1990 |
| Galaxkey Leap Limited | Information & communication | 2023 |
| Gale & Simpson Equities Ltd | Financial services | 2020 |
| Gale & Simpson Ltd | Financial services | 2015 |
| Gale Family Ltd | Real estate | 2024 |
| Gallant Developments Ltd | Real estate | 2021 |
| Galway Properties Ltd | Real estate | 2019 |
| Gamble OT Practice Ltd | Health & social care | 2026 |
| Game Trading Group Ltd | Wholesale & retail | 2022 |
| Gamebird Consulting Ltd | Professional & scientific | 2013 |
| Gamma Property Services Ltd | Real estate | 2024 |
| Gardens With Passion Limited | Administrative & support | 2024 |
| Gardius Limited | Professional & scientific | 2014 |
| Garnade Direct Limited | Construction | 2002 |
| Garrotech Ltd | Information & communication | 2018 |
| Garston Inns Limited | Hospitality | 2004 |
| Gartland and Mellina Group (Europe) Limited | Professional & scientific | 2015 |
| Garwood Coaching and Consulting Ltd | Administrative & support | 2021 |
| Gary Docks Ltd | Financial services | 2022 |
| GAS Bricks Ltd | Wholesale & retail | 2024 |
| GAS Heating and Plumbing Solutions Ltd | Construction | 2016 |
| GAS to Power Ltd | Information & communication | 2005 |
| GASMAN147 Limited | Administrative & support | 2017 |
| Gate House Aylesbury Ltd | Hospitality | 2021 |
| Gateway Platform Services Limited | Financial services | 2017 |
| Gateway Seed II (GP) LLP | | 2022 |
| Gateway Seed II LP | | 2022 |
| Gather Consulting Limited | Professional & scientific | 2016 |
| Gatsby Law Ltd | Professional & scientific | 2020 |
| GB Film Cars Limited | Transport & logistics | 2016 |
| GB Merchandise Limited | Professional & scientific | 2017 |
| GBC Watford Ltd | Hospitality | 2023 |
| GBS 2012 Limited | Professional & scientific | 2012 |
| GBS Diamond Drilling Limited | Construction | 2017 |
| GBS Plant Hire Ltd | Construction | 2022 |
| GC & SA Residents Association Limited | Professional & scientific | 2009 |
| GC Film Transport Limited | Transport & logistics | 2024 |
| Gcco Limited | Administrative & support | 2007 |
| GCJ Services Limited | Professional & scientific | 2024 |
| GD Design & Property Services Ltd | Real estate | 2025 |
| GE Trading and Consulting Limited | Real estate | 2020 |
| Geary Woods Construction Ltd | Construction | 2013 |
| Geary Woods Limited | Other services | 2005 |
| Gemini Beauty Brentwood Ltd | Other services | 2022 |
| Gemini Limited | Wholesale & retail | 2011 |
| Gemirgo Consultants Limited | Professional & scientific | 2022 |
| Gems (LT) Limited | Wholesale & retail | 2011 |
| Gena's Beauty Salon Ltd | Other services | 2023 |
| Gencob Engineering LP | | 2002 |
| Generius Ltd | Administrative & support | 2014 |
| Genesis Property Care Ltd | Administrative & support | 2025 |
| Genethics Ltd | Extraterritorial | 2023 |
| Geneva Musical Instruments Limited | Wholesale & retail | 2022 |
| Genius-I Limited | Professional & scientific | 2011 |
| Genome Productions Ltd | Professional & scientific | 2015 |
| Genrise.Ai Limited | Information & communication | 2023 |
| Gentian Limited | Professional & scientific | 2020 |
| Genuine Capital Ventures CV LLP | | 2023 |
| Genuine Capital Ventures LP | | 2022 |
| GEO Trading Limited | Professional & scientific | 2007 |
| Geodesic Aviation Ltd | Professional & scientific | 2022 |
| Geomares Publishing UK Ltd | Information & communication | 2016 |
| Geordie Dave Limited | Professional & scientific | 2014 |
| Georgie Rudd Coaching Ltd | Professional & scientific | 2020 |
| Geotheo Limited | Information & communication | 2012 |
| Geox Express Ltd | Transport & logistics | 2024 |
| Geraldes Limited | Arts & recreation | 2025 |
| Geranium Homes Limited | Real estate | 2026 |
| Gestalt in Vision Ltd | Information & communication | 2013 |
| GET Fitt Limited | Health & social care | 2004 |
| GET Healthy Ltd | Health & social care | 2022 |
| GET on Logistics Ltd | Transport & logistics | 2023 |
| GET Scheduled Limited | Information & communication | 2010 |
| Getscale Limited | Professional & scientific | 2023 |
| GFS Flex Limited | Wholesale & retail | 2017 |
| GGU Limited | Households | 2008 |