| Nediab Accountants Limited | Professional & scientific | 2019 |
| Nediab Accounting Company Limited | Professional & scientific | 1997 |
| Needed Services Ltd | Construction | 2020 |
| Neil Flynn Consulting Limited | Professional & scientific | 2009 |
| Neiome Ltd. | Professional & scientific | 1997 |
| Neit Ltd | Professional & scientific | 2024 |
| Nene View Limited | Construction | 2019 |
| Neobike Ltd | Wholesale & retail | 2025 |
| Neomounts UK Ltd | Wholesale & retail | 2020 |
| Neon Kiwi Ltd | Professional & scientific | 2026 |
| Neosilix Technologies Ltd | Professional & scientific | 2025 |
| Nevermore Tattoo Limited | Arts & recreation | 2016 |
| New Endeavours Limited | Construction | 2021 |
| New Image by Danielle Ltd | Other services | 2021 |
| New Moon Property Limited | Real estate | 2023 |
| New World Material Handling Ltd. | Manufacturing | 2023 |
| New World Motorsports Ltd | Wholesale & retail | 2024 |
| Newman Consultancy West Midlands Limited | Professional & scientific | 2016 |
| Next Chapter Divorce Settlement Ltd | Professional & scientific | 2026 |
| Next Flavour Kitchens Ltd | Hospitality | 2026 |
| Next to Nothing Discounts Ltd | Wholesale & retail | 2023 |
| Next Transport Ltd | Extraterritorial | 2017 |
| Nextmove Property Ltd | Real estate | 2025 |
| NH Henly Ltd | Hospitality | 2026 |
| Nichifor Group Ltd | Construction | 2017 |
| Nicholas Coleridge Limited | Professional & scientific | 2003 |
| Nick & G Transport Ltd | Transport & logistics | 2024 |
| Nicolae Caraman Ltd | Transport & logistics | 2017 |
| Nigel Mckie Ltd | Construction | 2007 |
| Nirvana Supplier Ltd | Wholesale & retail | 2020 |
| Nisa Transport Limited | Transport & logistics | 2020 |
| Nishkams Limited | Wholesale & retail | 2005 |
| Nivaro Ltd | Construction | 2024 |
| NJB Project Consultants Ltd | Information & communication | 2015 |
| NL Recovery Ltd | Professional & scientific | 2025 |
| NLE Equestrian Shop Ltd | Wholesale & retail | 2022 |
| NMN First Ltd | Construction | 2023 |
| NO Vacation Ltd | Transport & logistics | 2018 |
| Nobled Thermal Technology Gruppe Germany Ltd | Professional & scientific | 2014 |
| North Africa International Trade Co., Ltd | Professional & scientific | 2023 |
| North Kent Glazing Services Ltd | Construction | 2022 |
| North London Therapy Ltd | Health & social care | 2024 |
| Northampton Motor Movers Limited | Wholesale & retail | 2012 |
| Northampton Waste & Clearance Limited | Water & waste | 2026 |
| Northants GAS Services Limited | Construction | 2022 |
| Norwood Property Services Ltd | Real estate | 2022 |
| Notm Services Ltd | Professional & scientific | 2025 |
| Novak & Good Catering Ltd | Hospitality | 2025 |
| Novclean AG & Co Limited | Professional & scientific | 2014 |
| Nowak Elite Car Painting Ltd | Wholesale & retail | 2024 |
| NR14 Ltd | Professional & scientific | 2021 |
| NRB Management Ltd | Real estate | 2020 |
| NSJ Rentals Ltd | Real estate | 2021 |
| Number Crunchers Accountants Ltd | Professional & scientific | 2015 |
| Numerical Studio Ltd | Education | 2023 |
| Nuovo Detailing Ltd | Other services | 2025 |
| Nutmeg Spaces Limited | Real estate | 2026 |
| Nutrient Sciences Limited | Manufacturing | 1979 |
| Nyfield Developments Limited | Real estate | 2008 |
| Nyfield Group Limited | Financial services | 2024 |
| Nyfield Limited | Real estate | 2022 |
| Nyfield Properties Limited | Real estate | 2008 |
| O&E Technology Co., Ltd | Professional & scientific | 2009 |
| Oak & Stone Landscaping (Northampton) Ltd | Administrative & support | 2026 |
| Oakdale Products Holdings Ltd | Financial services | 2023 |
| Obies Property Ltd | Real estate | 2023 |
| Obsidian Performance Ltd | Wholesale & retail | 2026 |
| Ocean Point Property Investment LP | | 2004 |
| Ocean Wide Logistics UK Ltd | Transport & logistics | 2021 |
| Oceans Consulting Ltd | Professional & scientific | 2015 |
| Odnm Ltd | Professional & scientific | 2025 |
| Offord & Offord Ltd | Agriculture & fishing | 2025 |
| Ogee Business Park Ltd | Real estate | 2005 |
| OIL Tanks Plus Limited | Wholesale & retail | 2015 |
| OJI Marketing Ltd | Professional & scientific | 2017 |
| OJL Developments Ltd | Real estate | 2025 |
| OKU Ltd | Wholesale & retail | 2018 |
| Olaf Transport Ltd | Transport & logistics | 2018 |
| Old HC Ltd | Transport & logistics | 2018 |
| OLI Oils Ltd | Manufacturing | 2025 |
| Oliver Batho Limited | Professional & scientific | 2018 |
| Olivia Furniture Ltd | Wholesale & retail | 2017 |
| Olivin Online Limited | Wholesale & retail | 2020 |
| Olymp Logistic Ltd | Transport & logistics | 2019 |
| Omnia Creative Limited | Administrative & support | 2019 |
| Ondemand Consulting Ltd | Professional & scientific | 2023 |
| One in TEN Productions UK LLP | | 2013 |
| ONEGOAL88 Limited | Financial services | 2025 |
| Onet Developments Limited | Professional & scientific | 2023 |
| Online Property Port Ltd | Information & communication | 2023 |
| Ooda AI Solutions Ltd | Professional & scientific | 2025 |
| OPEN3I Limited | Information & communication | 2013 |
| Optimum Sustainability Limited | Professional & scientific | 2024 |
| Orange Eskimo Consulting Limited | Information & communication | 2026 |
| Orbital Travel & Taxi Limited | Transport & logistics | 2023 |
| Orbvita Journey Health and Wellness Coaching Ltd | Health & social care | 2024 |
| Orchard LEY Residents Management Limited | Real estate | 1986 |
| Original Gangster Ltd | Real estate | 2023 |
| Oriole Group Ltd | Real estate | 2026 |
| OSO 1989 Ltd | Wholesale & retail | 2018 |