| Nestify Developers Ltd | Real estate | 2024 |
| NET SET Go Tackle Ltd | Professional & scientific | 2023 |
| Netzero Tech Limited | Professional & scientific | 2022 |
| Neuro Art School Ltd | Education | 2022 |
| Neuro Art Solutions Ltd | Arts & recreation | 2021 |
| Neurodivergent Labour Limited | Other services | 2022 |
| New Cutting Image Limited | Other services | 2016 |
| New Smart Properties Investment Ltd | Real estate | 2025 |
| New Smart Properties Ltd | Real estate | 2023 |
| New Tech Life Ltd | Wholesale & retail | 2025 |
| New Venture Partners Ltd | Real estate | 2017 |
| New Vogue International Ltd | Wholesale & retail | 2024 |
| New York Nails & Spa Staines Ltd | Other services | 2025 |
| Newbridge Care Limited | Professional & scientific | 2019 |
| Newfloplumbing&Heating Ltd | Construction | 2023 |
| Newlane Leisure Limited | Arts & recreation | 1992 |
| Nexafri Group Ltd | Wholesale & retail | 2025 |
| Nexgen Protection Ltd | Administrative & support | 2025 |
| Nexisia Ltd | Information & communication | 2024 |
| Next Business Level Limited | Administrative & support | 2009 |
| Nexus Sports Advisory Ltd | Information & communication | 2026 |
| Ngomeks Services Ltd | Other services | 2019 |
| Nicholsons House Maidenhead Limited | Real estate | 2025 |
| Nijjer Concrete Pump UK Ltd | Construction | 2025 |
| Nimratconstruction Ltd | Construction | 2025 |
| Nine Grain Ltd | Wholesale & retail | 2021 |
| Nitya Hygiene Solutions Ltd | Administrative & support | 2023 |
| NJ Aesthetics Limited | Health & social care | 2024 |
| NJ Bookkeeping Solutions Limited | Professional & scientific | 2015 |
| NJB Roofing & Building Limited | Construction | 2016 |
| NJW7 Limited | Hospitality | 2024 |
| NK Import Cars Ltd | Wholesale & retail | 2022 |
| NM WPP Administration Ltd | Professional & scientific | 2023 |
| NO TAK Ltd | Hospitality | 2024 |
| Noble EGG Limited | Extraterritorial | 2006 |
| Noble Foods Group Limited | Financial services | 2006 |
| Noble Foods Holdings Limited | Financial services | 1996 |
| Noble Foods International Limited | Extraterritorial | 2015 |
| Noble Foods Limited | Manufacturing | 1998 |
| NOC Tech Limited | Information & communication | 2019 |
| Noisy Atom Ltd | Information & communication | 2012 |
| Nomadic Travellers Ltd | Administrative & support | 2016 |
| Norman Flats Limited | Households | 1991 |
| North West Surrey Integrated Care Services (Nics) Ltd | Health & social care | 2016 |
| Nourish Beauty Ltd | Other services | 2014 |
| Nova Blooms Limited | Wholesale & retail | 2019 |
| Nova-Sun Renewables Ltd | Construction | 2025 |
| Novaflip Ltd | Real estate | 2026 |
| NRM Interiors Limited | Construction | 2012 |
| NSG Design & Build Ltd | Construction | 2024 |
| Nteractive Consulting & Events Limited | Professional & scientific | 2010 |
| NU Consultancy Ltd | Information & communication | 2013 |
| Nuka Print Ltd | Wholesale & retail | 2019 |
| Nurseriesandschools Ltd | Information & communication | 2020 |
| Nutrition Tree Limited | Wholesale & retail | 2025 |
| Nuxit Limited | Information & communication | 2025 |
| NWT Capital Limited | Real estate | 2015 |
| Nyshex UK Limited | Information & communication | 2021 |
| O'Connor Plastering Limited | Construction | 2004 |
| Oak Tree Farm Developments Limited | Construction | 2021 |
| Oakhaven Investments Limited | Real estate | 2023 |
| Oakhill Consultancy Limited | Extraterritorial | 2020 |
| Oakleaf Recycling Limited | Water & waste | 2015 |
| Oaks Interior Design and Fine Finishings Limited | Construction | 2007 |
| Oaks Residents' Association Limited(The) | Households | 1983 |
| Oakwyn Skills Ltd | Professional & scientific | 2026 |
| Oast Court Management Company Limited | Households | 1987 |
| Oats to Go Ltd | Hospitality | 2025 |
| Object Equals Ltd | Information & communication | 2024 |
| OBM Systems Ltd | Information & communication | 2016 |
| Obsessed Media Limited | Professional & scientific | 2022 |
| Odart Heating and Plumbing Limited | Construction | 2013 |
| Offyouglow Ltd | Wholesale & retail | 2025 |
| Ojsb Limited | Information & communication | 2017 |
| Olby Holdings (Bognor Regis) Limited | Real estate | 1961 |
| Old Station Mews Management Company Staines Ltd | Households | 2020 |
| Old Wessex Tabletop Society Ltd | Hospitality | 2023 |
| Oleo London Ltd | Other services | 2025 |
| Olliehood Limited | Wholesale & retail | 2023 |
| Olukai Limited | Wholesale & retail | 2010 |
| Olumide Williams IT Services Limited | Information & communication | 2016 |
| Omni Networks Limited | Information & communication | 2007 |
| Omnitel Limited | Information & communication | 1994 |
| ON Call Handyman Limited | Administrative & support | 2011 |
| ON GOD Apparel Ltd | Manufacturing | 2026 |
| ON the Spot Broker Ltd | Transport & logistics | 2021 |
| On-Site Solutions Limited | Information & communication | 1993 |
| One HIT Drip E Liquid Limited | Real estate | 2019 |
| One Stop 25 Ltd | Administrative & support | 2025 |
| ONE2ONE Health Limited | Professional & scientific | 2012 |
| Oneclickhr Limited | Information & communication | 1996 |
| Onkaar Properties Limited | Real estate | 2022 |
| Online Sellers Circle Limited | Education | 2018 |
| Onovy Ltd | Wholesale & retail | 2024 |
| Opal Apartments Ltd | Financial services | 2010 |
| Opaline Studio Limited | Health & social care | 2025 |
| Opalmech Limited | Real estate | 1985 |
| Openway Investments Limited | Other services | 2011 |
| Opmundo Limited | Professional & scientific | 2021 |
| Option One Logistics Limited | Professional & scientific | 2004 |