| Noor Mist Perfumes Ltd | Wholesale & retail | 2025 |
| Noor Recycling Limited | Water & waste | 2025 |
| Noor&Deepmanes Concrete Ltd | Construction | 2025 |
| Noor-E-Madina Trading (Private) Limited | Wholesale & retail | 2024 |
| Noora Restaurant Ltd | Hospitality | 2023 |
| Nooransh Textile Limited | Wholesale & retail | 2024 |
| Noorie Fashions Limited | Wholesale & retail | 2010 |
| Noormahal Limited | Manufacturing | 2018 |
| Nooroop Ltd | Hospitality | 2018 |
| Nora's Domestic Cleaning Ltd | Households | 2018 |
| Noras Cleaning Company Limited | Administrative & support | 2005 |
| Norex Services Limited | Administrative & support | 2026 |
| Norix Ltd | Wholesale & retail | 2025 |
| Normill Southall Limited | Real estate | 2024 |
| North Road Meat Shop Ltd | Wholesale & retail | 2024 |
| Northcote Avenue Properties Limited | Real estate | 2016 |
| Northolt Primary Care Network Limited | Health & social care | 2023 |
| Northop Electronic Ltd | Manufacturing | 2025 |
| Norvex Trade Ltd | Wholesale & retail | 2026 |
| Norwood Developments (London) Limited | Construction | 2012 |
| Norwood Green Junior School | Education | 2013 |
| Norwood Green(Block B)Management Company Limited | Real estate | 1985 |
| Norwood Superstore Limited | Wholesale & retail | 2018 |
| NOT Just Curry's Limited | Hospitality | 2025 |
| Notorious Drummers Ltd | Arts & recreation | 2025 |
| Nour General Trading (UK) Limited | Agriculture & fishing | 2003 |
| Nova Electrical Wholesale Ltd | Wholesale & retail | 2020 |
| Nova Neural Labs Limited | Information & communication | 2025 |
| Novara Healthcare Limited | Health & social care | 2024 |
| Novarro Estates Limited | Real estate | 2020 |
| Novastrada Homes Ltd | Real estate | 2024 |
| Novastrada Ltd | Wholesale & retail | 2023 |
| Noveda Collective Limited | Hospitality | 2025 |
| Noventra Trend Ltd | Wholesale & retail | 2026 |
| Novo Dots Limited | Professional & scientific | 2015 |
| Novostar Limited | Hospitality | 2009 |
| NQB Passive Fire Protection Limited | Construction | 2026 |
| NR Communication Solutions Limited | Information & communication | 2014 |
| NS Gill Ltd | Transport & logistics | 2023 |
| Nsbn Ltd | Real estate | 2021 |
| NSG Logistics Ltd | Transport & logistics | 2025 |
| NSK Builders Ltd | Real estate | 2021 |
| NSR Buid Ltd | Construction | 2026 |
| NSS & JKS Investments Limited | Real estate | 2019 |
| NSS Limited | Manufacturing | 2001 |
| NT Retail Limited | Wholesale & retail | 2026 |
| NUBE9 Limited | Information & communication | 2024 |
| Nuded Ltd | Other services | 2024 |
| Nueh Limited | Information & communication | 2022 |
| Numan Khawar Ltd | Wholesale & retail | 2026 |
| Nunu Abess LP | | 2016 |
| Nurex Cargo and Clearing Ltd | Transport & logistics | 2020 |
| Nurv Group Limited | Construction | 2021 |
| NV Corporations Ltd | Financial services | 2018 |
| NWP Solutions Ltd | Administrative & support | 2026 |
| NXR Collection Ltd | Hospitality | 2025 |
| NXT GEN Health Ltd | Health & social care | 2024 |
| Nxt-Era. Ltd. | Professional & scientific | 2023 |
| NZ Trip UK Ltd | Administrative & support | 2025 |
| O&H FM Limited | Administrative & support | 2025 |
| O'Brien-Patel LLP | | 2021 |
| O'Brien-Patel Properties Limited | Real estate | 2023 |
| O.M.B. Investments Limited | Real estate | 2007 |
| O.S.N.S.Tea Limited | Wholesale & retail | 2014 |
| O2 Ventures Limited | Wholesale & retail | 2024 |
| O9VISTUS Civil & Design Ltd | Construction | 2024 |
| Oak Tree Investments (Hounslow) Limited | Real estate | 2026 |
| Oakend Investments Limited | Financial services | 2019 |
| Oakheart Homes Ltd | Health & social care | 2026 |
| Oakwood Care Centre Limited | Health & social care | 2015 |
| Oakwood Investments Limited | Real estate | 2025 |
| Oakwood Luxury Homes Ltd | Real estate | 2019 |
| Oases Digital Ltd | Information & communication | 2025 |
| Oasis Services Ltd | Administrative & support | 2019 |
| Oasis Staffing Ltd | Administrative & support | 2021 |
| Oatlands Holding Ltd | Real estate | 2026 |
| Obhan Holdings Limited | Real estate | 2024 |
| Obhan Projects Ltd | Construction | 2024 |
| Objective Care Limited | Administrative & support | 2007 |
| Obyi Health Limited | Health & social care | 2014 |
| OCC Grand Limited | Hospitality | 2025 |
| Ocean Chief's Ltd | Wholesale & retail | 2023 |
| Ocean Halal Pizza Ltd | Hospitality | 2025 |
| Oceanworld Trading Limited | Information & communication | 2019 |
| Octamber Limited | Administrative & support | 2009 |
| OD Movers Ltd | Transport & logistics | 2025 |
| Oddjobs Services Limited | Administrative & support | 2019 |
| Odeen Ltd | Wholesale & retail | 2025 |
| Official Corporate Ltd | Wholesale & retail | 2026 |
| Offland Cars Ltd | Wholesale & retail | 2023 |
| Ohiijat Contractors Ltd | Construction | 2025 |
| Ohmnix Limited | Information & communication | 2019 |
| OK Valeting London Ltd | Wholesale & retail | 2020 |
| Okiyo Limited | Construction | 2025 |
| OLA Gomez Ltd | Extraterritorial | 2000 |
| Old Mpororo Locum Limited | Health & social care | 2021 |
| Old Park Mews Property Limited | Real estate | 2023 |
| Old Village Limited | Hospitality | 2025 |
| Olithan Ltd | Wholesale & retail | 2024 |
| Oliver’S Bullion Ltd | Wholesale & retail | 2025 |