| Outspoken Community CIC | Education | 2025 |
| Outwood Logistics Ltd | Transport & logistics | 2014 |
| Outwrk Ltd | Wholesale & retail | 2026 |
| Oval Property Group Limited | Households | 2020 |
| Over the Garden Wall Limited | Wholesale & retail | 2016 |
| Overnest Limited | Professional & scientific | 2017 |
| Overton (Leic) Ltd | Financial services | 2020 |
| Overton Brothers Ltd | Construction | 2010 |
| Overture Capital Limited | Financial services | 2014 |
| Ovicta Limited | Financial services | 2019 |
| Ovidiu Stanciu 1989 Limited | Transport & logistics | 2019 |
| Ovidiu Tureatca Ltd | Transport & logistics | 2018 |
| Ovio Ltd | Wholesale & retail | 2024 |
| OVO House Leicester LLP | | 2021 |
| OW Canada Ltd | Professional & scientific | 2025 |
| OW Dubai Ltd | Professional & scientific | 2025 |
| OW Holdings UK Ltd | Professional & scientific | 2025 |
| OW India Ltd | Professional & scientific | 2026 |
| OW Qatar Ltd | Professional & scientific | 2025 |
| Owethukaidenm Limited | Health & social care | 2025 |
| OWL GET IT Ltd | Transport & logistics | 2015 |
| OWL Optics Ltd | Health & social care | 2023 |
| Owlc Consulting Ltd | Professional & scientific | 2014 |
| Owlight Ltd | Information & communication | 2019 |
| Owlthorpe Ltd | Transport & logistics | 2015 |
| Ownz Club Ltd | Other services | 2019 |
| Ownz Group Ltd | Financial services | 2017 |
| Ownz International Ltd | Professional & scientific | 2016 |
| Ownz Maintenance Ltd | Construction | 2021 |
| Ownz Management Ltd | Real estate | 2018 |
| Ownz Property Ltd | Real estate | 2018 |
| Ownz Wholesale Ltd | Wholesale & retail | 2018 |
| Owolade Ltd | Health & social care | 2021 |
| Owrfc (Trading) Ltd | Arts & recreation | 2017 |
| OX Haulage Ltd | Transport & logistics | 2026 |
| Oxbow Investments Ltd | Real estate | 2024 |
| Oxbridge Gardens Ltd | Education | 2020 |
| Oxbridge International Limited | Administrative & support | 2025 |
| Oxenic Limited | Information & communication | 2015 |
| Oxford AI Consulting Ltd | Information & communication | 2018 |
| Oxford College of Studies Ltd | Education | 2021 |
| Oxford College Online Ltd | Education | 2025 |
| Oxford Metropolitan College (UK) Limited | Education | 2023 |
| Oxfordum Limited | Construction | 2019 |
| Oxlade & Swift Associates Limited | Professional & scientific | 1986 |
| Oxley Façades Ltd | Education | 2019 |
| OXO69 Ltd | Wholesale & retail | 2020 |
| Oxygen Boost Leicestershire Ltd | Health & social care | 2024 |
| Oxygen JET Ltd | Arts & recreation | 2025 |
| Oxygen Studios Limited | Real estate | 2023 |
| Oxygenise Limited | Wholesale & retail | 2018 |
| Oxygn Plus Limited | Real estate | 2023 |
| Oyees Concept Ltd | Manufacturing | 2026 |
| OZ & OZ Ltd | Wholesale & retail | 2016 |
| Ozbal Construction Ltd | Construction | 2020 |
| Ozir Limited | Professional & scientific | 2019 |
| Ozlo Media Ltd | Information & communication | 2026 |
| Ozmn Ltd | Health & social care | 2023 |
| Ozonemarketplace Ltd | Wholesale & retail | 2019 |
| Ozrika Investments Ltd | Real estate | 2024 |
| Ozun Group Limited | Wholesale & retail | 2026 |
| Ozzi Ltd | Wholesale & retail | 2019 |
| Ozzy's Flames Ltd | Hospitality | 2023 |
| O’Neill Family Holdings Ltd | Financial services | 2025 |
| O’Reilly Access Ltd | Construction | 2022 |
| P & G Exim UK Ltd | Wholesale & retail | 2025 |
| P & H Convenience Ltd | Wholesale & retail | 2022 |
| P & J (Leicester) Limited | Real estate | 1974 |
| P & J Walker Property Ltd | Real estate | 2018 |
| P & K Patterns Limited | Manufacturing | 2001 |
| P & L Forecourt Services Limited | Professional & scientific | 2007 |
| P & L Investments Limited | Real estate | 2003 |
| P & L Knitwear Limited | Manufacturing | 2003 |
| P & M Trading & Sons Ltd | Manufacturing | 2004 |
| P & P Cabs Ltd | Transport & logistics | 2022 |
| P & P Investments (Leic) Ltd | Real estate | 2024 |
| P & P Pizza Limited | Hospitality | 2026 |
| P & R Build Limited | Construction | 2019 |
| P & R Store Ltd | Real estate | 2022 |
| P & S Mander Ltd | Real estate | 2024 |
| P & Y Catering Ltd | Hospitality | 2024 |
| P a Funerals Limited | Other services | 2009 |
| P a Todd and Co Ltd | Professional & scientific | 2012 |
| P and J Plumbing & Heating Limited | Construction | 2011 |
| P B GAS Services Limited | Manufacturing | 2020 |
| P Best Games Limited | Hospitality | 2016 |
| P C Construction & Groundworks Ltd | Construction | 2019 |
| P C Leicester Ltd | Construction | 2015 |
| P C Motor Group Leicester Ltd | Wholesale & retail | 2025 |
| P C Nwabugwu Ltd | Health & social care | 2022 |
| P Cooper & Associates Limited | Professional & scientific | 2006 |
| P F Chantrell Holdings Limited | Professional & scientific | 2023 |
| P F Chantrell Investments Limited | Financial services | 2023 |
| P G Motors (Leicester) Ltd | Wholesale & retail | 2003 |
| P Garrington & Sons Properties Limited | Construction | 2023 |
| P H Duct Fitting Limited | Energy | 2015 |
| P Hudson Holdings Ltd | Financial services | 2022 |
| P J and J B Glennon and Sons Limited | Construction | 2001 |
| P J Buckingham Ltd | Real estate | 2007 |
| P J Gilbert Service and Maintenance Ltd | Manufacturing | 2019 |