| Nofinity Ltd | Manufacturing | 2022 |
| Norsaca (Trading) Limited | Health & social care | 2012 |
| North Farm Development Management Company Limited | Households | 2020 |
| North Horizon Limited | Professional & scientific | 2025 |
| North Midland Electrical (Worksop) Ltd | Manufacturing | 2019 |
| North Notts BID Limited | Administrative & support | 2017 |
| North Notts Community Leisure Limited | Arts & recreation | 2005 |
| North Notts Fishing & Shooting Limited | Wholesale & retail | 2020 |
| North Scope Property Limited | Real estate | 2025 |
| Northern Alfa Performance Ltd | Wholesale & retail | 2014 |
| Northern Garden Supplies Incorporating Northern Swimming Pools Ltd | Wholesale & retail | 1998 |
| Northern Gaskets Limited | Manufacturing | 2021 |
| Northern Plant and Machinery Limited | Manufacturing | 2024 |
| Nosh Spice Limited | Hospitality | 2022 |
| Noteworthy Global Ltd | Information & communication | 2023 |
| Nottingham City Couriers Limited | Transport & logistics | 2021 |
| Nottinghamshire Home Care Ltd | Health & social care | 2024 |
| Nottinghamshire Women's AID Limited | Other services | 1984 |
| Notts Fire & Electrical Ltd | Manufacturing | 2025 |
| Nova AGE Ltd | Wholesale & retail | 2024 |
| Nova Glow Nottingham Ltd | Other services | 2025 |
| Nova Trade Frames Limited | Extraterritorial | 1995 |
| NRH Catering Ltd | Hospitality | 2023 |
| Nunns Taxis Ltd | Transport & logistics | 2017 |
| Nuthatch Group Limited | Real estate | 2026 |
| NV Sharp Alliance Ltd | Administrative & support | 2021 |
| Oakham Construction Nottinghamshire Limited | Construction | 2020 |
| Oakhills Residential Homes Limited | Health & social care | 2004 |
| Oakrange Calibration Ltd | Professional & scientific | 2022 |
| Oakrange Engineering Limited | Manufacturing | 1982 |
| Obeche Ltd | Professional & scientific | 2012 |
| Obeche Properties Ltd | Real estate | 2023 |
| OBI Deco Ltd | Construction | 2025 |
| OBI Homes Limited | Real estate | 2018 |
| Ocean B5 Limited | Construction | 2025 |
| Ocero Limited | Professional & scientific | 2013 |
| Oilsmart Ltd | Wholesale & retail | 2024 |
| OK Butcher Ltd | Wholesale & retail | 2022 |
| Oladin Ltd | Transport & logistics | 2016 |
| Olawa Bakery Ltd | Manufacturing | 2015 |
| Olawa Bakery Nottingham Ltd | Wholesale & retail | 2021 |
| Old Brewery Garage Limited | Wholesale & retail | 2026 |
| Oldewinter Ltd | Arts & recreation | 2024 |
| Olive Design Limited | Professional & scientific | 2002 |
| Olive Grove Worksop Limited | Hospitality | 2010 |
| Oliver Transport Incorporation Ltd | Transport & logistics | 2019 |
| Omega Motor Company Limited | Wholesale & retail | 2017 |
| Omska Retail Ltd | Wholesale & retail | 2025 |
| Omstrad Limited | Construction | 2023 |
| ON Power Ltd | Energy | 2026 |
| Oncalldoc Company Limited | Health & social care | 2014 |
| Oneiro Digital Global Ltd | Professional & scientific | 2025 |
| Onetouch Method Ltd | Construction | 2023 |
| Onward Media Ltd | Information & communication | 2026 |
| Ooco Ltd | Professional & scientific | 2025 |
| Opecon Limited | Mining & quarrying | 1989 |
| Optimise Behaviour Consultants Ltd | Professional & scientific | 2024 |
| Optimum Property Solutions Ltd | Real estate | 2018 |
| Optivite International Limited | Manufacturing | 1989 |
| Optivite Limited | Extraterritorial | 1987 |
| Opus Whitwell Limited | Other services | 2020 |
| Orbitedge London Ltd | Construction | 2025 |
| Orchard Farm (Yorkshire) Ltd | Agriculture & fishing | 2019 |
| Orchard Pension Solutions Limited | Administrative & support | 2025 |
| Orego-Stim Limited | Extraterritorial | 2014 |
| Orion Partnership LLP | | 2023 |
| Orluneuk Ltd | Administrative & support | 2025 |
| Osberton Mill Farm Ltd | Agriculture & fishing | 2022 |
| Osberton Nurseries Limited | Professional & scientific | 2010 |
| Osiyaz Ltd | Wholesale & retail | 2025 |
| OSP Cottage Limited | Real estate | 2020 |
| Otlo Brokers (UK) Limited | Wholesale & retail | 2016 |
| OUR Local Builder Ltd | Construction | 2023 |
| Outdoor Comps Limited | Arts & recreation | 2025 |
| Overtek Ltd | Wholesale & retail | 2008 |
| P & C Screeding Services Ltd | Construction | 2014 |
| P & G Bookkeeping Services Ltd | Professional & scientific | 2025 |
| P & J Enginerring Ltd | Manufacturing | 2026 |
| P & O Holdings Limited | Extraterritorial | 2014 |
| P Abbott Properties Ltd | Real estate | 2026 |
| P L P Property Services (Yorkshire) Limited | Real estate | 1999 |
| P Sunnar & a Sunnar Limited | Health & social care | 2018 |
| P Sunnar and a Sunnar Holdings Ltd | Real estate | 2025 |
| P Sunnar and a Sunnar Property Ltd | Real estate | 2025 |
| P.T. Logistics Ltd | Transport & logistics | 2025 |
| P1 Race Engineering Ltd | Arts & recreation | 2020 |
| P1 Real Estate Ltd | Real estate | 2023 |
| P3D-LAB Ltd | Manufacturing | 2014 |
| P3MA Ltd | Information & communication | 2009 |
| Pamanther Ltd | Health & social care | 2009 |
| Pandora Lettings Ltd | Real estate | 2024 |
| Pandrol (Vortok) Limited | Manufacturing | 1975 |
| Pandrol International Limited | Financial services | 1945 |
| Pandrol Limited | Manufacturing | 1953 |
| Pandrol Pension Trustees Limited | Extraterritorial | 2000 |
| Pandrol Rail Fastenings Limited | Financial services | 1980 |
| Park Farm Land Limited | Agriculture & fishing | 1996 |
| Park Panels Precast Limited | Manufacturing | 2008 |
| Parkers Crystals Ltd | Wholesale & retail | 2016 |
| Parsons Training Ltd | Professional & scientific | 2013 |