| Negative Carbon Renewables Limited | Professional & scientific | 2022 |
| Nellieblu Communications Limited | Information & communication | 2023 |
| Network Armour (International) Limited | Information & communication | 2023 |
| Network Armour (UK) Limited | Information & communication | 2023 |
| Network Armour Limited | Information & communication | 1997 |
| New Leaf Nurseries Limited | Agriculture & fishing | 2025 |
| New Look Windows and Conservatories Limited | Construction | 2012 |
| Newbridge (Louth) Ltd | Households | 2009 |
| Newmarket Management Company (Louth) Ltd | Real estate | 2021 |
| Nextgen Property Developers Limited | Construction | 2023 |
| NH Group Holdings Limited | Financial services | 2020 |
| Nicanda Limited | Wholesale & retail | 2007 |
| Nicetidy Limited | Financial services | 2025 |
| Nicky Wright Limited | Arts & recreation | 2003 |
| Niko Imports Ltd | Wholesale & retail | 2021 |
| NJ & CL Herbert and Sons Ltd | Real estate | 2024 |
| NJR Construction Ltd | Construction | 2025 |
| NL Plant Nurseries Limited | Agriculture & fishing | 2025 |
| Noble Thornton Limited | Construction | 2019 |
| Nomadic Speed Limited | Professional & scientific | 2013 |
| Nordic Seafood UK Limited | Wholesale & retail | 2006 |
| Norge-Tech Limited | Professional & scientific | 2017 |
| Norpol Packaging Limited | Manufacturing | 1993 |
| North Holdings (Lincs) Limited | Financial services | 2026 |
| North Lincs Innovations Limited | Extraterritorial | 2015 |
| North Marketing Digital Ltd | Professional & scientific | 2026 |
| Northolme Leisure Ltd | Hospitality | 2021 |
| Nova Barber 92 Ltd | Other services | 2026 |
| NRL Roofing Ltd | Construction | 2011 |
| NS - LEC Limited | Construction | 2016 |
| Nsrenewables Consultancy Ltd | Professional & scientific | 2026 |
| O&R Group Limited | Extraterritorial | 2018 |
| Oak Ridge Hotels Limited | Hospitality | 2005 |
| Oaktrees and Busibodies Childrens Nurseries Limited | Education | 2017 |
| Oaktrees Children Nurseries Limited | Education | 2013 |
| OH SEW Sweet Ltd | Wholesale & retail | 2015 |
| Old Dairy Yard Management Company Limited | Households | 2013 |
| Old School Architects LLP | | 2016 |
| Old School Saltfleetby Limited | Hospitality | 2022 |
| OLI Stubbs Next Generation Investments Ltd | Financial services | 2024 |
| Oliversoft Ltd | Information & communication | 2011 |
| Ollf Events Ltd | Hospitality | 2024 |
| Olsten Developments Ltd | Construction | 2016 |
| Olsten Trout Limited | Agriculture & fishing | 2004 |
| Omersa and Company Limited | Manufacturing | 2002 |
| Oml.Property Limited | Real estate | 2025 |
| Operta Consulting Services Ltd | Professional & scientific | 2023 |
| Opus Plus Limited | Professional & scientific | 2015 |
| Orion Computers Limited | Wholesale & retail | 2020 |
| Oxford Farming Conference(The) | Education | 1986 |
| Ozsay Ltd | Hospitality | 2013 |
| P & S Products & Refreshening Limited | Professional & scientific | 2011 |
| P H Mountain Corrugated Limited | Manufacturing | 2001 |
| P Thomas Domestic Services Ltd | Administrative & support | 2011 |
| P W C Marine Consultants Limited | Professional & scientific | 2011 |
| P Z Walmsley Services Ltd | Administrative & support | 2025 |
| Pack Horse Louth Ltd | Hospitality | 2018 |
| Paint Shield Pro Limited | Wholesale & retail | 2018 |
| Paperoki Limited | Agriculture & fishing | 2008 |
| Parabellum Projects Limited | Manufacturing | 1992 |
| Parker Asset Holdings Ltd | Financial services | 2015 |
| Parker Products Limited | Manufacturing | 2013 |
| Parkers Travel Ltd | Transport & logistics | 2023 |
| Parkinson Reid Group Ltd | Real estate | 2024 |
| Parks Wealth Management (PWM) Limited | Professional & scientific | 2024 |
| Parks Wealth Management Limited | Financial services | 2018 |
| Parks Wills & Estate Planning Ltd | Administrative & support | 2017 |
| Paul Richmond Wealth Management LLP | | 2026 |
| Paul Roberts Dance Limited | Professional & scientific | 2010 |
| PC Vending Services Limited | Hospitality | 2016 |
| Pemberley Consultants Limited | Professional & scientific | 2019 |
| Pendennis Foods Limited | Agriculture & fishing | 1955 |
| Performance Technical Racing Limited | Administrative & support | 2008 |
| Perkins Installations Limited | Construction | 2014 |
| Permaximum Ltd | Professional & scientific | 2021 |
| Personalised Gift Products Ltd. | Wholesale & retail | 2015 |
| Pest Detective Ltd | Administrative & support | 2023 |
| Pest Lincs Ltd | Professional & scientific | 2020 |
| Peter Hobson (Louth) Limited | Extraterritorial | 1992 |
| Petworth Cosmorama Limited | Construction | 1997 |
| Pfbuxtongroup Limited | Professional & scientific | 2023 |
| Pink Skip Co UK Limited | Professional & scientific | 2008 |
| Pizza Paradise (Louth) Limited | Hospitality | 2020 |
| PJT Vertical Ltd | Professional & scientific | 2025 |
| Plant Propagators Limited | Other services | 1995 |
| Plantec Limited | Manufacturing | 2018 |
| PMM Hotels Ltd | Hospitality | 2015 |
| PMW Safety Limited | Extraterritorial | 2015 |
| Polar Network Solutions Limited | Information & communication | 2026 |
| Pompeii Hospitality Ltd | Hospitality | 2026 |
| Pots of Distinction Limited | Wholesale & retail | 2011 |
| Power Machine Systems Ltd | Manufacturing | 2014 |
| Pozzani Pure Water Limited | Manufacturing | 1988 |
| Precious Renewable Consultancy Limited | Professional & scientific | 2019 |
| Precision Nutrition Limited | | 2024 |
| Premier Paint & Bodyworx Limited | Wholesale & retail | 2021 |
| Prestige Power Wash Lincs Ltd | Administrative & support | 2026 |
| Pretty 1098 Limited | Health & social care | 2006 |
| Primary Care Lincolnshire Medical Services Limited | Administrative & support | 2017 |
| Primavera Meadows Limited | Agriculture & fishing | 2009 |