| Novahome D&N Ltd | Real estate | 2025 |
| Novak Panpro Limited | Administrative & support | 2010 |
| Novamala Ltd | Manufacturing | 2025 |
| Novellini (UK) Limited | Wholesale & retail | 1993 |
| Novellini Bathroom Products Limited | Extraterritorial | 1985 |
| November Four Films Limited | Information & communication | 2019 |
| Novo Indus Ltd | Agriculture & fishing | 2013 |
| Novum Refurbishments Limited | Construction | 2019 |
| Novus 1 Limited | Professional & scientific | 2013 |
| Novus Coxhoe DC Limited | Information & communication | 2025 |
| Novus Renewable Services II Limited | Financial services | 2025 |
| Novus RS Midco 1 Limited | Financial services | 2025 |
| Novus Sheq Limited | Administrative & support | 2022 |
| Novus Solar Developments Limited | Professional & scientific | 2013 |
| Novus Solar Limited | Professional & scientific | 2012 |
| NOX Commercial Interiors Ltd | Construction | 2023 |
| Noxta Ltd | Hospitality | 2026 |
| Noyes Lewis Commercial Property Limited | Real estate | 2013 |
| Noz-Alls Limited | Manufacturing | 1996 |
| Nozzle Ltd | Professional & scientific | 2021 |
| Npdom Construction Ltd | Construction | 2025 |
| Nprojx Limited | Professional & scientific | 2011 |
| NR Aftercare Limited | Other services | 2021 |
| NRA Health Limited | Health & social care | 2024 |
| NRG Soft Limited | Information & communication | 2009 |
| Nrnr Limited | Professional & scientific | 2019 |
| Nrsk LLP | | 2010 |
| NSB Events Ltd | Arts & recreation | 2023 |
| NSD4 Limited | Professional & scientific | 2015 |
| NSD5 Limited | Professional & scientific | 2015 |
| NSF Design & Build Limited | Other services | 2013 |
| NSF Health Ltd. | Health & social care | 2016 |
| NSG Worcestershire Ltd | Education | 2025 |
| Nsight Ltd | Administrative & support | 2024 |
| Nsknox Technologies UK Ltd | Administrative & support | 2025 |
| NSM Management Company Limited | Real estate | 2011 |
| NSP Logistics Ltd | Transport & logistics | 2020 |
| Nspire People Ltd | Administrative & support | 2020 |
| Nssr Fresh Ltd | Wholesale & retail | 2025 |
| Nssr Sushi Ltd | Wholesale & retail | 2025 |
| Ntsynapse Technologies Limited | Information & communication | 2025 |
| Nu-Clear Ltd | Other services | 2020 |
| Nu-Lite Glass and Glazing Limited | Manufacturing | 2024 |
| NUA Project Management Limited | Financial services | 2007 |
| Nuant UK Limited | Information & communication | 2022 |
| Nude Developments Limited | Construction | 2015 |
| Nuera Homes Ltd | Construction | 2014 |
| Number 8 Rotunda Ltd | Real estate | 2024 |
| Number Seven Lansdown Terrace Residents Association Limited | Hospitality | 1980 |
| Number Seven Royal Parade Residents Association Limited | Professional & scientific | 1980 |
| Numerga Limited | Professional & scientific | 2021 |
| Nuns of the Tundra Ltd | Wholesale & retail | 2025 |
| Nursery School Providers Limited | Real estate | 2018 |
| Nurved Ltd | Information & communication | 2009 |
| Nutfield Nursery (Surrey) Limited | Health & social care | 2024 |
| Nutrition in Sport Ltd | Arts & recreation | 2016 |
| Nuts Activewear Limited | Wholesale & retail | 2024 |
| Nuvo Property Group Ltd | Real estate | 2024 |
| Nuvolon Ltd | Information & communication | 2025 |
| Nuyu Cheltenham Ltd | Health & social care | 2024 |
| Nuyu Dental Ltd | Health & social care | 2024 |
| NVC Properties Limited | Real estate | 2017 |
| NVP Holdings Ltd | Financial services | 2025 |
| NVP Ventures Ltd | Financial services | 2025 |
| Nxtgen Scaffolding (Southwest) Ltd | Construction | 2021 |
| Nyar K'Odero Group Limited | Information & communication | 2018 |
| NYN2016 Ltd | Other services | 2016 |
| NZL Chiro Limited | Health & social care | 2017 |
| O & M Life & Pensions Ltd. | Information & communication | 1992 |
| O J Enterprises Limited | Administrative & support | 2025 |
| O&P Property Ltd | Financial services | 2022 |
| O'Brien & Price Cheltenham Limited | Professional & scientific | 2003 |
| O'Brien GAS Services Limited | Other services | 2003 |
| O'Brien Metals Ltd | Water & waste | 2017 |
| O'Brien Properties (SW) Limited | Real estate | 2024 |
| O'Briens Metals Llandeilo Limited | Wholesale & retail | 2026 |
| O'Connor Construction Company Limited | Construction | 1986 |
| O'Neill & O'Neill Limited | Health & social care | 2011 |
| O'Outlandish Limited | Hospitality | 2024 |
| Oak & Stone Cotswold Developments Limited | Construction | 2020 |
| Oak Books Limited | Professional & scientific | 2021 |
| Oak Care Home Services Ltd | Health & social care | 2024 |
| Oak Court Management (NO.1) Limited | Households | 1992 |
| Oak Court Management (NO.2) Limited | Households | 1993 |
| Oak Financial Consultants Limited | Real estate | 2014 |
| Oak House Nursery School Ltd | Health & social care | 2011 |
| Oak Manor Management Company Limited | Households | 1986 |
| Oak Technology Limited | Information & communication | 2006 |
| Oak Tree View Limited | Real estate | 2026 |
| Oakdale Software Limited | Information & communication | 1993 |
| Oakey Ltd | Construction | 2011 |
| Oakhurst Court (Cheltenham) Management Company Limited | Households | 2003 |
| Oaklands Care Home Property Ltd | Real estate | 2024 |
| Oaklands Manor Care Home Ltd | Health & social care | 2024 |
| Oaklands Manor Property Ltd | Real estate | 2024 |
| Oakley Hall Mansion House Management Limited | Households | 1998 |
| Oakleys Biomass Limited | Professional & scientific | 2023 |
| Oakmont Education Services Limited | Education | 2022 |
| Oakmont Services Group Ltd | Health & social care | 2019 |
| Oaks Farm Solar Limited | Energy | 2022 |