| Munrose FD Services Limited | Financial services | 2013 |
| Munrose Limited | Health & social care | 2003 |
| Murell Sales Limited | Wholesale & retail | 2014 |
| Murray Road Management Co. Limited | Real estate | 1986 |
| Musculoskeletal Physio Clinic Ltd | Health & social care | 2017 |
| Musings Limited | Professional & scientific | 2024 |
| Mutell Limited | Real estate | 1965 |
| Mutualfruit Limited | Professional & scientific | 2009 |
| My Consultancy Ltd | Administrative & support | 2018 |
| My London LET Ltd | Hospitality | 2020 |
| My Visage My Teeth Limited | Health & social care | 2014 |
| My West 5 Limited | Health & social care | 2014 |
| Mychildsdoctor Limited | Information & communication | 2014 |
| Myhobbycourses Ltd | Information & communication | 2019 |
| Myprimeshop Ltd | Wholesale & retail | 2025 |
| Mystic Flame Ltd | Manufacturing | 2025 |
| N & B Investments Limited | Real estate | 2002 |
| N DE Mario & Mario Limited | Administrative & support | 2015 |
| N Shah Consulting Ltd | Real estate | 2018 |
| N&P Holdings Ltd | Financial services | 2021 |
| N2 Vision Limited | Wholesale & retail | 2024 |
| N7 Corporation Ltd | Administrative & support | 2019 |
| Naan Staap (Harrow) Ltd | Hospitality | 2023 |
| Nagle JAY Limited | Professional & scientific | 2002 |
| Nagle Properties Limited | Real estate | 1997 |
| Najm Group Limited | Real estate | 2025 |
| Nanomarketing UK Ltd | Information & communication | 2012 |
| NAP Media Limited | Information & communication | 2021 |
| Narayan Investments Ltd | Financial services | 2015 |
| Nardodipace Asset Management Ltd | Households | 2023 |
| Narita Assets Limited | Real estate | 2012 |
| Natalie Wansbrough-Jones Ltd | Professional & scientific | 2013 |
| Natellect Ltd | Information & communication | 2025 |
| Nathan Primecare Limited | Professional & scientific | 2013 |
| Nathwani Dental Ltd | Health & social care | 2014 |
| Natural Resource Advisors Limited | Professional & scientific | 2011 |
| Navian Limited | Professional & scientific | 2025 |
| Navkaar Properties Ltd | Real estate | 2020 |
| Nazma Ltd | Hospitality | 2019 |
| NBL Builders Ltd | Construction | 2018 |
| Ncdiagnostics Ltd | Wholesale & retail | 2019 |
| NCT Services (London) Limited | Transport & logistics | 2021 |
| NCW Ltd | Wholesale & retail | 2018 |
| ND Properties Trustee Ltd | Financial services | 2020 |
| Nd&S Ltd | Real estate | 2021 |
| Neasden Electronics Limited | Wholesale & retail | 1980 |
| Neasden Property Investments Limited | Construction | 2020 |
| Nebrija Heights Limited | Professional & scientific | 2018 |
| Necaprice Limited | Real estate | 1996 |
| Neema Pauls Real Estates Limited | Real estate | 2005 |
| Neenoo Limited | Wholesale & retail | 2017 |
| Neetikas Couture Limited | Wholesale & retail | 2013 |
| Neilson Global Trade Limited | Wholesale & retail | 2025 |
| Nelly's Choice Limited | Manufacturing | 2024 |
| Neomedic Limited | Manufacturing | 1997 |
| Nessora Ltd | Wholesale & retail | 2025 |
| Network Energy Assessing Limited | Other services | 2023 |
| Neuropsychology Clinic Limited | Health & social care | 2024 |
| New BIZ Solutions Ltd | Professional & scientific | 2011 |
| New Cafe Hill Ltd | Hospitality | 2023 |
| New DMC Investments Limited | Real estate | 2018 |
| New Energy London Limited | Other services | 2024 |
| New GEN Consultancy Ltd | Information & communication | 2025 |
| New Universe UK Ltd | Wholesale & retail | 2011 |
| Newell (Northwood) Limited | Households | 1982 |
| Newgrange of Cheshunt Limited | Health & social care | 2008 |
| Newmarket (U.K.) Holdings Limited | Professional & scientific | 1999 |
| Newport Lane Management Limited | Households | 2007 |
| Newtone Heating & Plumbing Ltd | Construction | 2026 |
| Next Chapter Limited | Information & communication | 2016 |
| Nicola Thomas Consultancy Ltd | Administrative & support | 2015 |
| Nicole Estates Ltd | Real estate | 2022 |
| Nigel Perks Consulting Limited | Professional & scientific | 2016 |
| Night Air Entertainment Limited | Information & communication | 2021 |
| Nihit Gyan Advisory Ltd | Information & communication | 2025 |
| Niko Shipping Limited | Extraterritorial | 2000 |
| Nimika Retail Ltd | Wholesale & retail | 2020 |
| Niroja Supermarket Ltd | Wholesale & retail | 2023 |
| Nisha Radia Limited | Health & social care | 2025 |
| Nishiki Design Limited | Information & communication | 2020 |
| Nishk Properties Ltd | Real estate | 2020 |
| Niti Advisors Limited | Professional & scientific | 2025 |
| NJC Tickets & Events Ltd | Other services | 2011 |
| Njobvu Entertainment Limited | Information & communication | 2021 |
| NN Bhatti Construction Limited | Construction | 2015 |
| NO Limit E.Xh Ltd | Transport & logistics | 2023 |
| NO. 13 Consultancy Limited | Professional & scientific | 2026 |
| Nobel Construction Services Ltd | Construction | 2019 |
| Nocolu Limited | Hospitality | 2019 |
| Noisecrime Studios Ltd | Information & communication | 2017 |
| Nooks & Crannies Limited | Professional & scientific | 2004 |
| Noor Sisters Network Limited | Hospitality | 2025 |
| Nordixfitness Ltd | Manufacturing | 2019 |
| North London Renovation Ltd | Construction | 2014 |
| Northolt Tyre Service Limited | Other services | 1961 |
| Northway Care Ltd | Health & social care | 2026 |
| Northwood Property Investments Ltd | Real estate | 2020 |
| Northwood Accident Repair Centre Ltd | Wholesale & retail | 2023 |
| Northwood Auto Repairs Ltd | Wholesale & retail | 2026 |
| Northwood Beauty Salon Limited | Other services | 2019 |