| Omni Investment Group Ltd | Real estate | 2025 |
| Omni Investments L.P. | | 2015 |
| Omni Light Carry LP | | 2022 |
| Omni Light CI Partner LP | | 2022 |
| Omni Merces Incentive LP | | 2023 |
| Omni Rentals Ltd | Administrative & support | 2025 |
| Omni Supply Company L.P. | | 2011 |
| Omni Support Systems LP | | 2014 |
| Omni Taverns Holdings Limited | Administrative & support | 2019 |
| Omnia Performance Limited | Arts & recreation | 2021 |
| Omnia Scot Ltd | Transport & logistics | 2023 |
| Omnia Scotland Limited | Administrative & support | 2006 |
| Omnibloom Ltd | Health & social care | 2025 |
| Omnicare Pharmacy Limited | Administrative & support | 2003 |
| Omniearth Ltd | Wholesale & retail | 2018 |
| Omnirex Business L.P. | | 2011 |
| Omnisafe Limited | Other services | 1995 |
| Omnitex Inter LP | | 2012 |
| Omnitex Trading LP | | 2015 |
| Omnium International LP | | 2019 |
| Omnixdev Ltd | Information & communication | 2026 |
| Omonileola Brands Ltd | Wholesale & retail | 2025 |
| OMP (GP) Limited | Financial services | 2008 |
| OMS UK Branch L.P. | | 2013 |
| Omsa International LP | | 2016 |
| Omvio Ltd | Wholesale & retail | 2025 |
| ON Axis Ltd | Manufacturing | 2021 |
| ON Guard Security Solutions Ltd | Administrative & support | 2025 |
| ON Pink Sand Ltd | Information & communication | 2011 |
| ON Site Services (Fife) Limited | Construction | 2009 |
| ON Strategy Ltd | Professional & scientific | 2025 |
| ON the Move (Scotland) Ltd | Real estate | 2023 |
| ON the Sky Ltd | Professional & scientific | 2026 |
| ON Tour Campervans Ltd | Administrative & support | 2023 |
| On-Site Relaxation Limited | Health & social care | 2004 |
| ON5 Corporation LP | | 2015 |
| ON5 Intelli LP | | 2016 |
| ON99 Trading Ltd | Professional & scientific | 2025 |
| ONA XV Ltd | Wholesale & retail | 2026 |
| Onarach Ltd | Professional & scientific | 2026 |
| Once Upon a Vyne Ltd | Arts & recreation | 2025 |
| Oncloud Consulting (Scotland) Ltd | Information & communication | 2018 |
| Oncobiopharm Limited | Professional & scientific | 2005 |
| Oncocine Ltd | Professional & scientific | 2025 |
| Onconom Limited | Professional & scientific | 2022 |
| Ondalinda Limited | Other services | 2024 |
| Onderia LP | | 2015 |
| Ondine Restaurants Ltd. | Hospitality | 2012 |
| One 36 Computing Limited | Information & communication | 2004 |
| One 61 Security Ltd | Financial services | 2025 |
| One 7 Prop Co Limited | Real estate | 2022 |
| One Accounting Ltd | Professional & scientific | 2007 |
| One Addington Ltd | Wholesale & retail | 2021 |
| One ASH Properties Ltd | Real estate | 2022 |
| One BED Ltd | Wholesale & retail | 2026 |
| One Canada Square (Retail) Unit Trust GP Limited | Real estate | 2006 |
| One Canada Square (Retail) Unit Trust LP Limited | Real estate | 2006 |
| One Cherry Ltd | Information & communication | 2018 |
| One Click Marketing Limited | Professional & scientific | 2003 |
| One Cloud Service Ltd | Information & communication | 2019 |
| One CNC CH46 Ltd | Construction | 2026 |
| One Designed Ltd | Professional & scientific | 2023 |
| One Edge Partners Ltd | Wholesale & retail | 2023 |
| One Eighty Solutions Ltd | Wholesale & retail | 2024 |
| One Eleven Consulting Limited | Professional & scientific | 2018 |
| One Exip LP | | 2014 |
| One Good Idea Limited | Manufacturing | 1997 |
| One Great Bottle Limited | Wholesale & retail | 2024 |
| One Hash Limited | Wholesale & retail | 2026 |
| One Hundred Flowers Limited | Professional & scientific | 2016 |
| One MAN AD Solutions LP | | 2022 |
| One Market Ecom Ltd | Wholesale & retail | 2026 |
| One Media TV LP | | 2016 |
| One MTX Derby Ltd | Construction | 2025 |
| One MTX Leics Ltd | Construction | 2025 |
| One MTX Mansf Ltd | Construction | 2025 |
| One MTX Notts Ltd | Construction | 2025 |
| One Parent Families Scotland | Health & social care | 1985 |
| One Quest (Europe) Ltd | Administrative & support | 2023 |
| One Recruitment (Glasgow) Ltd | Administrative & support | 2015 |
| One Reid Ltd | Wholesale & retail | 2022 |
| One Scotland Limited Partnership | | 2019 |
| One Shop Invest LP | | 2017 |
| One Solution International LP | | 2015 |
| One Stone Advisors Ltd | Professional & scientific | 2009 |
| One Stop Shop Business Services Limited | Extraterritorial | 2024 |
| One Time Pass Driving School Ltd | Education | 2025 |
| One Twelve Twenty-Six Limited | Real estate | 2017 |
| One Txindoki SP | | 2000 |
| One UP Plastering Ltd | Construction | 2023 |
| One World Alliance LP | | 2015 |
| One World Shop | Wholesale & retail | 1985 |
| One-Ticket Limited | Transport & logistics | 2001 |
| ONE20 Holdings Ltd | Hospitality | 2024 |
| Onecity Limited | Other services | 2007 |
| Onecrew Edin Limited | Hospitality | 2026 |
| Oneflo Labs Ltd | Wholesale & retail | 2019 |
| Oneill Glasgow Ltd | Real estate | 2020 |
| Onekind Charity | Professional & scientific | 1995 |
| Onestepaccess Limited | Education | 2008 |