| Grantham Manufacturing Limited | Manufacturing | 1985 |
| Grantham Mini Market Ltd | Wholesale & retail | 2018 |
| Grantham Projects Limited | Construction | 2024 |
| Grantham Property Partnership LLP | | 2014 |
| Grantham Quality Meat Company Limited | Wholesale & retail | 1997 |
| Grantham Re-Upholstery Limited | Other services | 2013 |
| Grantham Refrigeration and Air Conditioning Ltd | Construction | 2006 |
| Grantham Renewable Energy Limited | Construction | 2022 |
| Grantham Security Ltd | Administrative & support | 2025 |
| Grantham Self Store Limited | Households | 2007 |
| Grantham Senior Citizens Club and Community Centre Limited | Other services | 2011 |
| Grantham Storage Ltd | Transport & logistics | 2022 |
| Grantham Taxis (25) Ltd | Transport & logistics | 2025 |
| Grantham Taxis (UK) Ltd | Wholesale & retail | 2017 |
| Grantham Tennis Club Limited | Arts & recreation | 2011 |
| Grantham Tennis Club Members Limited | Arts & recreation | 2011 |
| Grantham Tennis Club Trading Limited | Arts & recreation | 2011 |
| Grantham Town Football Club Limited | Arts & recreation | 1934 |
| Grantham Truck Services Limited | Wholesale & retail | 2006 |
| Grantham Utility Limited | Administrative & support | 2017 |
| Grantham Venues & Business Solutions Ltd | Administrative & support | 2022 |
| Granthamthai Limited | Hospitality | 2024 |
| Grass Care Ltd | Real estate | 2021 |
| Gravity FM CIC | Extraterritorial | 2007 |
| Great Lodge Experience Limited | Financial services | 2013 |
| Greatest Hand Car Wash Ltd | Other services | 2025 |
| Grebe Limited | Real estate | 2025 |
| Green Lane Association Limited | Other services | 2005 |
| Green Mountain Trading Limited | Professional & scientific | 2005 |
| Green Room Investments Ltd | Hospitality | 2018 |
| Greenacres Storage Company Limited | Transport & logistics | 2000 |
| Greenalo LLP | | 2007 |
| Greendog K9 Services Limited | Other services | 2022 |
| Greenerlife Energy Limited | Construction | 2023 |
| Greenhouse Sayers Ltd | Financial services | 2025 |
| Greenland UK Care Ltd | Health & social care | 2024 |
| Greenlifecare Limited | Public administration | 2024 |
| Greens-Empire Ltd | Financial services | 2026 |
| Greetwell LLP | | 2009 |
| Greg Darmon Window Cleaning Services Limited | Administrative & support | 2008 |
| Greyhound Capital LLP | | 2009 |
| Griffin Safety Management Services Ltd | Professional & scientific | 2012 |
| Grimsby Fish & Chips Limited | Hospitality | 2023 |
| Grip Happens Ltd | Wholesale & retail | 2026 |
| Gromett Limited | Real estate | 2015 |
| Groop Labs Ltd | Information & communication | 2025 |
| Grouptrevly Ltd | Wholesale & retail | 2025 |
| Grow Your Own Marketing Ltd | Professional & scientific | 2014 |
| Gryphon Capital Limited | Financial services | 2013 |
| Gryphon Event Safety and Security Ltd | Administrative & support | 2013 |
| GS Investment Group Limited | Financial services | 2022 |
| GS Underwriting Limited | Financial services | 2005 |
| GSC Assets Limited | Other services | 2025 |
| GSD 24/7 Ltd | Construction | 2018 |
| GSL Networking Ltd | Information & communication | 2008 |
| GSS Holding Group Limited | Financial services | 2022 |
| GT Outlet UK Limited | Wholesale & retail | 2021 |
| Gtfc Catering Ltd | Hospitality | 2015 |
| Gtfc Youth Development Ltd | Education | 2017 |
| Gulbrandsen E C Ltd | Wholesale & retail | 1994 |
| Gulliver Risk Management LLP | | 2007 |
| Gurkha Property Investment Ltd | Real estate | 2015 |
| Guru Media Ltd | Information & communication | 2019 |
| Gutierrez TDL Ltd | Wholesale & retail | 2025 |
| Gwenwich (UK) Limited | Information & communication | 2008 |
| H & C Investments Limited | Professional & scientific | 2012 |
| H Building and Restoration Ltd | Construction | 2021 |
| H R & J Building Services Ltd | Construction | 2011 |
| H&M Painting Plaster Decorations Ltd | Real estate | 2020 |
| H&S Commercial Services Ltd | Professional & scientific | 2015 |
| Hairworx of Oakham Limited | Other services | 2013 |
| Hall Underwriting Limited | Financial services | 1998 |
| HAM Nominees Limited | Professional & scientific | 2009 |
| Hambleton Developments Limited | Construction | 2018 |
| Hamblin Birbeck Holdings Ltd | Financial services | 2026 |
| Hamblys IFA Ltd | Financial services | 2020 |
| Hamy Grantham Limited | Wholesale & retail | 2019 |
| HAN Holdings Limited | Financial services | 2021 |
| Hanbeck Farm Ltd | Hospitality | 2020 |
| Hanby Farms Limited | Agriculture & fishing | 1946 |
| Hanby Nominees Limited | Professional & scientific | 2009 |
| Handley Chase Commercial Centre Limited | Households | 2018 |
| Handley Chase Sleaford Community Interest Company | Other services | 2018 |
| Hani Models Ltd | Administrative & support | 2024 |
| Happy Strong and Healthy Limited | Other services | 2010 |
| Harcourt (Lincs) Ltd | Construction | 2019 |
| Harcourt 2015 Ltd | Real estate | 2013 |
| Harcourt Developments (Lincs) Limited | Real estate | 2017 |
| Hardman-Brown Ltd. | Information & communication | 2014 |
| Hardwick & ORR Finance Ltd | Financial services | 2025 |
| HAREVE25 | Financial services | 2025 |
| Hargrave Timber Sales Limited | Wholesale & retail | 2015 |
| Harlaxton & Edinburgh Ltd | Financial services | 2023 |
| Harlaxton Bowls Club Limited | Arts & recreation | 2026 |
| Harlaxton College | Education | 2009 |
| Harlaxton Energy Networks Limited | Energy | 2010 |
| Harlaxton Engineering Services Limited | Construction | 1998 |
| Harlaxton Farming Company LLP | | 2012 |
| Harlaxton GAS Networks Ltd | Energy | 2015 |
| Harlaxton Holdings Limited | Construction | 2015 |