| Gemini Metal Roofing & Cladding Ltd | Construction | 2023 |
| Gemma L Davie Ltd | Professional & scientific | 2024 |
| Gemz Fashion Ltd | Wholesale & retail | 2026 |
| Genie UK Limited | Construction | 1989 |
| Genkihope Ltd | Administrative & support | 2020 |
| Geoporte UK Ltd | Professional & scientific | 2025 |
| George Austin Group Ltd | Professional & scientific | 2019 |
| George C.Warr & SON Limited | Real estate | 1948 |
| George Hotel Limited | Hospitality | 2024 |
| GES Estates Ltd | Real estate | 2021 |
| Getaccomplished Ltd | Professional & scientific | 2025 |
| GFC NXT GEN Coaching Ltd | Education | 2025 |
| GHP Trading Limited | Transport & logistics | 2012 |
| Ghps One Ltd | Professional & scientific | 2024 |
| Giant London Limited | Professional & scientific | 2020 |
| Giant Steps Renovation Limited | Construction | 2006 |
| Gifted & Talented Enterprises Ltd | Education | 2018 |
| Gigabit Utility Supplies Ltd | Wholesale & retail | 2023 |
| Gilchrist Control Systems Limited | Professional & scientific | 1999 |
| Gilded Reef Limited | Real estate | 2019 |
| Gilder Grids Limited | Manufacturing | 2013 |
| Gillon Underwriting Limited | Financial services | 2009 |
| Gilmour and Holland Holdings Limited | Financial services | 2014 |
| Giltwick Limited | Information & communication | 2021 |
| Girlis Beauty Accessories Ltd | Households | 2010 |
| Gitellspon Ltd | Wholesale & retail | 2022 |
| Gkds Properties Ltd | Real estate | 2026 |
| GLA Interiors Limited | Construction | 2018 |
| Glaunsharoon Limited | Financial services | 2009 |
| Glen-Esk Grantham Ltd | Wholesale & retail | 2016 |
| Glencairn Campbell LLP | | 2012 |
| Glenrich Limited | Professional & scientific | 2003 |
| Glenside Country Practice Limited | Wholesale & retail | 2021 |
| GLI 2020 Limited | Real estate | 2006 |
| Glim Social Media and Creative Agency Ltd | Professional & scientific | 2025 |
| Global Campaign and Communication Management Limited | Administrative & support | 2020 |
| Global Entertainment Consulting Ltd | Other services | 2025 |
| Global Impact Club Ltd | Professional & scientific | 2024 |
| Global Operations Support Solutions Ltd | Wholesale & retail | 2025 |
| Global Roots Ltd | Agriculture & fishing | 2016 |
| Globalscale Limited | Hospitality | 2006 |
| Glossy Nails MT Ltd | Other services | 2026 |
| Gmluk Ltd | Manufacturing | 2022 |
| Go Office Furniture Limited | Professional & scientific | 2017 |
| Goddard U/W Limited | Financial services | 2020 |
| Gogo International Group Ltd | Wholesale & retail | 2025 |
| Goktas Limited | Hospitality | 2019 |
| Gold Results Ltd | Hospitality | 2019 |
| Golden Everest Limited | Wholesale & retail | 2014 |
| Golden Lady (UK) Limited | Wholesale & retail | 1986 |
| Golden Years Equine Retreat Ltd | Agriculture & fishing | 2025 |
| Goldfield Care UK Ltd | Health & social care | 2023 |
| Goldholme Brick, Stone and Landscape Products Ltd | Manufacturing | 2016 |
| Golightly Plastering Limited | Construction | 2025 |
| Gonerby Court Management Company Limited | Households | 2006 |
| Gonerby Developments Ltd | Real estate | 2023 |
| Gonerby Moor Farms Limited | Agriculture & fishing | 1956 |
| Gonna BEE Good Ltd | Arts & recreation | 2026 |
| Good Health Grantham Ltd | Other services | 2022 |
| Goodhart Limited | Financial services | 1998 |
| Goodliffe Retail Limited | Wholesale & retail | 2026 |
| GOR Buildings Limited | Construction | 2025 |
| Gorsebush Holdings Ltd | Real estate | 2026 |
| Gorsebush Limited | Information & communication | 2016 |
| GP Blend UK Ltd | Wholesale & retail | 2021 |
| Grab & Go Grantham Ltd | Wholesale & retail | 2024 |
| Grace Physiotherapy Ltd | Other services | 2023 |
| Graham a Smith Limited | Professional & scientific | 2009 |
| Graham Building Company Limited | Construction | 2010 |
| Graham Building Interiors Limited | Construction | 2023 |
| Graham Wade Farms Limited | Agriculture & fishing | 2011 |
| Gramen Limited | Administrative & support | 2008 |
| Grand Food Solutions Ltd | Hospitality | 2017 |
| Grant Boonzaier Ltd | Real estate | 2025 |
| Grantham & Newark Sunbeds Limited | Administrative & support | 2003 |
| Grantham and District Mencap Limited | Health & social care | 1986 |
| Grantham Archway Guesthouse Limited | Hospitality | 2023 |
| Grantham Arts CIC | Arts & recreation | 2020 |
| Grantham Autocare Limited | Wholesale & retail | 2014 |
| Grantham Barbers Limited | Other services | 2024 |
| Grantham Beauty Ltd | Other services | 2015 |
| Grantham Beauty Rooms Ltd | Other services | 2023 |
| Grantham Capital Limited | Real estate | 2018 |
| Grantham Car Shop LLP | | 2008 |
| Grantham Carpets Limited | Wholesale & retail | 2012 |
| Grantham Community Heritage Association Limited | Arts & recreation | 2011 |
| Grantham Creates C.I.C. | Arts & recreation | 2024 |
| Grantham Cricket Club Limited | Arts & recreation | 2014 |
| Grantham Designer Outlet Village Limited | Real estate | 2024 |
| Grantham Fabrications Holdings Limited | Financial services | 2021 |
| Grantham Food Ltd | Hospitality | 2022 |
| Grantham Gates Ltd | Manufacturing | 2016 |
| Grantham Gymnastics Limited | Arts & recreation | 2017 |
| Grantham Health Store Ltd | Wholesale & retail | 2011 |
| Grantham Home Care Limited | Health & social care | 2025 |
| Grantham Home Interiors Ltd | Wholesale & retail | 2015 |
| Grantham Hot Tubs Ltd | Administrative & support | 2021 |
| Grantham Investments Limited | Real estate | 1964 |
| Grantham Leisure Ltd | Manufacturing | 2016 |
| Grantham Local Shop Ltd | Wholesale & retail | 2026 |