| Norrels Drive (East Horsley) Limited | Households | 1993 |
| Northbank House Management Company Limited | Households | 2018 |
| Northcape Capital Ltd | Financial services | 2020 |
| Nosco Limited | Information & communication | 2010 |
| Nosco Property Limited | Financial services | 2024 |
| Not-For-Profit Finance Director Limited | Professional & scientific | 2019 |
| Notes London Ltd | Wholesale & retail | 2021 |
| NOW Assist Limited | Information & communication | 2022 |
| Nower Lodge Management Company Ltd | Households | 2006 |
| Nowkandi Ltd | Transport & logistics | 2016 |
| NP Building & Landscaping Ltd | Construction | 2025 |
| Ntelligent Limited | Information & communication | 2024 |
| NU2RITION Limited | Wholesale & retail | 1998 |
| Nuaera Ltd | Information & communication | 2010 |
| Nurestani Fresh Food Ltd | Hospitality | 2019 |
| Nutkins Day Nursery Limited | Health & social care | 2018 |
| Nutkins Property Services Limited | Administrative & support | 2019 |
| Nutriffic Ltd | Health & social care | 2016 |
| Nuval Group Ltd | Construction | 2022 |
| Nuvola Talent Services Ltd | Professional & scientific | 2022 |
| Nyati UK Limited | Construction | 2023 |
| OA2 Adults Limited | Education | 2001 |
| Oak Clover Ltd | Real estate | 2025 |
| Oak Grove Residents Company Limited | Households | 1994 |
| Oak Meadows Middleton ST George (Management Company) Limited | Households | 2022 |
| Oak Tree Gardens Management Limited | Households | 2007 |
| Oakbridge Group (Surrey) Ltd | Administrative & support | 2024 |
| Oakbridge Home Support Ltd | Health & social care | 2026 |
| Oakfields Properties Ltd | Real estate | 2025 |
| Oakglade Ltd | Information & communication | 2026 |
| Oaksend Close Management Company Limited | Households | 2007 |
| Oakwood Drive and Oakwood Close Residents Company Limited | Households | 1974 |
| Oakwood Park (Guildford) Management Company Limited | Households | 2002 |
| Oatlands Chase Weybridge (Management Company) Limited | Households | 2001 |
| Oatlands Reach Limited | Households | 2007 |
| OB Platforms Limited | Wholesale & retail | 2008 |
| Obsv.Ai Limited | Professional & scientific | 2025 |
| Obvious Marketing Ltd. | Professional & scientific | 2003 |
| OC Orthodontics Ltd | Health & social care | 2023 |
| Oceanus Charter Ltd | Arts & recreation | 2020 |
| Oceanwood Capital Management LLP | | 2006 |
| Ockham Strategy Limited | Professional & scientific | 2020 |
| Octavius RE Ltd | Construction | 2016 |
| Octillia Limited | Professional & scientific | 2012 |
| Office Affairs Limited | Professional & scientific | 2006 |
| Office Zebra Ltd | Administrative & support | 2012 |
| Officiate Ltd | Information & communication | 2023 |
| OH OH Ltd | Information & communication | 2023 |
| OH SO Good Ltd | Wholesale & retail | 2022 |
| OH Structures Limited | Professional & scientific | 2021 |
| Ohana LLP | | 2003 |
| Old Joy Ltd | Information & communication | 2020 |
| Old Mill East Molesey Management Company Limited | Households | 2015 |
| Old Rectory Lane Management Limited | Other services | 1982 |
| Old Town Mews (Farnham) Management Company Limited | Households | 1997 |
| Old World Plastering Ltd | Construction | 2020 |
| Oliver Court (Slough) Management Company Limited | Households | 2006 |
| Ollesso Limited | Information & communication | 2018 |
| Omega Strategies Ltd | Construction | 2019 |
| OMG Graphics & Signs Limited | Professional & scientific | 2021 |
| Omlc Capital LP | | 2012 |
| Omni Recruitment Ltd | Administrative & support | 2018 |
| Omnipulse Ltd | Professional & scientific | 2025 |
| ON the REC Limited | Hospitality | 2025 |
| One Mizuho Ltd | Manufacturing | 2013 |
| One Motor Group Ltd | Wholesale & retail | 2024 |
| Oneguy&O Ltd | Hospitality | 2024 |
| Online Growth Ltd | Professional & scientific | 2024 |
| Ontheline Performance Tennis Limited | Arts & recreation | 2012 |
| Onthewall Awards Ltd | Professional & scientific | 2024 |
| Open ALL Hours Fetcham Limited | Wholesale & retail | 2026 |
| Opius Art Ltd | Wholesale & retail | 2014 |
| Optamax Limited | Information & communication | 2025 |
| Optima Recruitment Limited | Administrative & support | 2007 |
| Optimum Excellence Method Ltd | Professional & scientific | 2018 |
| Optimum Services EM Limited | Construction | 2014 |
| Options Autism (1.1) Limited | Extraterritorial | 2001 |
| Options Autism (1.2) Limited | Extraterritorial | 1998 |
| Opulent Web Limited | Professional & scientific | 2025 |
| Opus Broadcast Limited | Information & communication | 2006 |
| Opus Lighting Limited | Wholesale & retail | 2012 |
| Orbury Consulting Limited | Professional & scientific | 2025 |
| Orchard Hill Property Services Limited | Other services | 2023 |
| Orchard Plumbing and Heating (Basingstoke) Limited | Construction | 2015 |
| Orford Construct Ltd | Professional & scientific | 2023 |
| Orford Digital Ltd | Professional & scientific | 2026 |
| Organized Chaos Limited | Information & communication | 2017 |
| ORI & Art Cafe Ltd | Hospitality | 2025 |
| Original Digital Limited | Information & communication | 2020 |
| Orindis Delicatessen Limited | Hospitality | 2003 |
| Ormond Rotating Equipment Ltd | Professional & scientific | 2014 |
| Ortho Clinic (Surrey) Limited | Health & social care | 2008 |
| Orwin Products Limited | Professional & scientific | 1977 |
| Oryx E4 Limited | Information & communication | 2015 |
| Oscarvale Ltd | Hospitality | 1996 |
| Osprey Close (Fetcham) Management Limited | Households | 1992 |
| Osprey Contracts Holdings Limited | Financial services | 2026 |
| Osprey Property Developments Limited | Construction | 2011 |
| Otoantiques Ltd | Wholesale & retail | 2024 |
| Ottopt Ltd | Manufacturing | 2013 |