| N.A.S. Electrical Limited | Construction | 2010 |
| N.C.C. Minerals Limited | Extraterritorial | 1965 |
| N.D.A. Engineering Equipment Limited | Wholesale & retail | 1978 |
| N.D.R. Limited | Wholesale & retail | 1992 |
| N.M. Associates Limited | Manufacturing | 1980 |
| N.P.S Time Pieces Ltd | Wholesale & retail | 2026 |
| N.U London Ltd | Financial services | 2019 |
| N.W.N. Developments Limited | Construction | 1999 |
| N2K Tours Limited | Administrative & support | 2018 |
| N3 ST. Luke's RTM Company Limited | Households | 2025 |
| N37 Ltd | Professional & scientific | 2019 |
| NA Soft Limited | Information & communication | 2015 |
| Nabel S& M Ltd | Manufacturing | 2019 |
| Nabha Solutions Limited | Information & communication | 2011 |
| Nadson Consulting Limited | Administrative & support | 2025 |
| Nagyal Traders Ltd | Wholesale & retail | 2019 |
| Nails by KIM Ltd | Other services | 2025 |
| Naina Kalidas Morjaria Limited | Information & communication | 2014 |
| Naina Music Ltd | Arts & recreation | 2025 |
| Nair Estates Ltd | Financial services | 2023 |
| Naisha Tours & Consultancy UK Ltd | Transport & logistics | 2024 |
| Naji Car Base Limited | Professional & scientific | 2024 |
| Nakka Consultancy Ltd | Information & communication | 2018 |
| Nakkashi Limited | Wholesale & retail | 2021 |
| Nalu Dream Ltd | Wholesale & retail | 2023 |
| Namo Technologies Ltd | Information & communication | 2011 |
| Namu Limited | Real estate | 2012 |
| Nana's Kingston Ltd | Hospitality | 2024 |
| Nana's Restaurants Ltd | Hospitality | 2022 |
| Nanbelle Limited | Information & communication | 2019 |
| Nandini Technologies Ltd | Information & communication | 2011 |
| Naneez Solutions Ltd | Information & communication | 2015 |
| Nanet Consultancy Ltd | Information & communication | 2021 |
| Nankani Enterprises Ltd | Wholesale & retail | 2024 |
| Nano-A Ltd | Real estate | 2026 |
| Naomi Tracz Jewellery Limited | Arts & recreation | 2010 |
| NAR Design Management Limited | Professional & scientific | 2023 |
| Nargis Zahid Ltd | Health & social care | 2025 |
| Narkap Ltd | Real estate | 2024 |
| Narottam TM Ltd | Professional & scientific | 2018 |
| Narrative House Ltd. | Professional & scientific | 2021 |
| Narrd Ltd | Construction | 2020 |
| Narsimha Tech Ltd | Information & communication | 2024 |
| Nascot Developments Ltd | Real estate | 2018 |
| Nascot Grange (Watford) Management Limited | Households | 2011 |
| Nascot Investments Ltd | Real estate | 2026 |
| Nascot Langley Ltd | Professional & scientific | 2026 |
| Nascot Properties Limited | Real estate | 1953 |
| Nascot Property Ltd | Real estate | 2022 |
| Nash Enterprises Ltd | Administrative & support | 2023 |
| Nashmo Limited | Wholesale & retail | 1992 |
| Nastasia Ltd | Transport & logistics | 2022 |
| Natalie Dennis Ltd | Manufacturing | 1998 |
| Natarajan Investments Limited | Real estate | 2021 |
| Nathan GEE Limited | Information & communication | 2025 |
| Nathansayers Creative Ltd | Professional & scientific | 2019 |
| Nathe Limited | Hospitality | 2025 |
| Nathoo Estates Ltd | Real estate | 2016 |
| Nati Medical Consulting Ltd | Professional & scientific | 2024 |
| National Animal Welfare Trust | Administrative & support | 2001 |
| Nationgate Property Limited | Hospitality | 2015 |
| Natissi Consulting Ltd | Professional & scientific | 2016 |
| Natlee Limited | Construction | 2025 |
| Natraj Homes Ltd | Real estate | 2021 |
| Natroceutics UK Ltd | Health & social care | 2022 |
| Natural Readings Ltd | Information & communication | 2020 |
| Naturallyours Limited | Health & social care | 2019 |
| Naturals PVT Limited | Hospitality | 2024 |
| Nautilusmax Ltd | Health & social care | 2023 |
| NAV Durga Maha Shakti Peeth | Other services | 2025 |
| NAV Medics Ltd | Health & social care | 2022 |
| NAV Property Ltd | Real estate | 2021 |
| Navana Cafe Limited | Hospitality | 2025 |
| Navara Ltd | Administrative & support | 2025 |
| Navarra LEE Medical Ltd | Health & social care | 2024 |
| Navek Consultancy Ltd | Professional & scientific | 2023 |
| Navii Systems and Engineering Services Limited | Professional & scientific | 2024 |
| Navkar Consulting Ltd | Professional & scientific | 2019 |
| Navkar Living Limited | Real estate | 2025 |
| NAVL23 Limited | Other services | 2020 |
| Navrang Construction Ltd | Construction | 2022 |
| Navsaria Trading Limited | Other services | 2012 |
| Navtech Consultancy Limited | Information & communication | 2013 |
| Navya School of Dance Ltd | Wholesale & retail | 2025 |
| Naylan Services Limited | Professional & scientific | 2007 |
| Nazir-An Property Ltd | Real estate | 2024 |
| Nazmo Limited | Real estate | 2020 |
| NB Trader Solutions Limited | Information & communication | 2013 |
| NBA Watford Limited | Real estate | 2023 |
| NBC Europe Ltd. | Financial services | 2011 |
| Nbnrs Ltd | Extraterritorial | 2014 |
| NCO London Ltd | Wholesale & retail | 2008 |
| ND Build and Clean Ltd | Construction | 2020 |
| ND Tiling Ltd | Construction | 2023 |
| ND Trade Limited | Wholesale & retail | 2005 |
| NDA Trading and Consulting Limited | Professional & scientific | 2014 |
| NDC Business Services Limited | Wholesale & retail | 2014 |
| Ndemic Creations Ltd | Information & communication | 2012 |
| NDG Services Ltd | Information & communication | 2023 |
| Ndpowerbi Limited | Information & communication | 2022 |