| Johnhill Investments Ltd | Financial services | 2023 |
| Johnny Autos Ltd | Wholesale & retail | 2020 |
| Johnny Bites Ltd | Hospitality | 2020 |
| Johnny Custard Limited | Hospitality | 2017 |
| Johnny Prince Limited | Financial services | 2026 |
| Johnsam Ltd | Real estate | 2011 |
| Johnson Astills Limited | Professional & scientific | 2021 |
| Johnson Astills Trustees Limited | Administrative & support | 2025 |
| Johnson Climate Solutions Ltd | Energy | 2026 |
| Johnson James Care Limited | Health & social care | 2017 |
| Johnson Orthotic Services Ltd | Health & social care | 2016 |
| Johnson's Countryside Services Ltd | Financial services | 2026 |
| Johnston Vulcanising and Services Limited | Professional & scientific | 2024 |
| Johny Construction Ltd | Manufacturing | 2026 |
| Johny Software Ltd | Wholesale & retail | 2026 |
| Jointeffort Communications Ltd | Construction | 2023 |
| Joji and NAN Investment Limited | Public administration | 2025 |
| Jojo Group Limited | Administrative & support | 2023 |
| Jokings Educare Ltd | Education | 2012 |
| Jokings International College Limited | Education | 2012 |
| Jokings International Limited | Administrative & support | 2011 |
| Jollof Republic Limited | Hospitality | 2020 |
| Jolly Group Holdings Limited | Financial services | 2024 |
| Jolly Group Limited | Hospitality | 2015 |
| Jolly Vending Services Limited | Hospitality | 1999 |
| Joluso Limited | Administrative & support | 2026 |
| Jomanda Limited | Wholesale & retail | 2005 |
| Jomia Engineering Ltd | Professional & scientific | 2024 |
| Jomondani Ltd | Health & social care | 2021 |
| JON Attfield Art Ltd | Arts & recreation | 2022 |
| Jonah Plumbing & Heating Ltd | Construction | 2023 |
| Jonathan Field Interpreting Ltd | Professional & scientific | 2023 |
| Jonathan Stuart Street Consulting Ltd | Professional & scientific | 2012 |
| Jonathan's Fireworks Displays Ltd | Arts & recreation | 2013 |
| Jonathan's Fireworks Limited | Wholesale & retail | 2000 |
| Jones & Duffin Solicitors (Leicester) Limited | Professional & scientific | 2020 |
| Jones & Jones Properties Ltd | Construction | 2021 |
| Jones & Shipman Hardinge Limited | Wholesale & retail | 1937 |
| Jones and Burnham Limited | Wholesale & retail | 2009 |
| Jones Groundworks Ltd | Construction | 2022 |
| Jones Plumbing Solutions Limited | Construction | 2012 |
| Jones Samuel Limited | Other services | 1986 |
| Jones Warrington Ltd | Administrative & support | 2020 |
| Jonesstudios Limited | Information & communication | 2019 |
| Jonetty Eco Yarns Ltd | Wholesale & retail | 2019 |
| Jonimel GE Limited | Health & social care | 2018 |
| Jonny Appleton Limited | Professional & scientific | 2012 |
| Jonny Concrete Limited | Construction | 2015 |
| Jonry Tasty Bite Limited | Wholesale & retail | 2017 |
| Jonstar Energy Brokers Ltd | Energy | 2015 |
| Jonstar Holdings Ltd | Financial services | 2023 |
| Jonstar Sustainable Technologies Ltd | Construction | 2020 |
| Jool Distribution Ltd | Transport & logistics | 2020 |
| Jora House Ltd | Wholesale & retail | 2024 |
| Jordan & Dryden Mediation Ltd | Professional & scientific | 2022 |
| Jordan Guitars Ltd | Wholesale & retail | 2021 |
| Jordan Motors Limited | Wholesale & retail | 2017 |
| Jordan Property Holdings Ltd | Real estate | 2022 |
| Jordans Perspective Limited | Professional & scientific | 2023 |
| Jordean Court RTM Company Ltd | Households | 2017 |
| Joren Digital UK Ltd | Information & communication | 2025 |
| Jorge Laurance Bespoke Furniture Ltd | Manufacturing | 2025 |
| Jorge Laurance by Design Limited | Manufacturing | 2017 |
| Jorge Motors Limited | Wholesale & retail | 2026 |
| Jorie Hair Ltd | Wholesale & retail | 2020 |
| Jorja Limited | Construction | 2010 |
| Josan Construction Ltd | Construction | 2017 |
| Josan GAS and Plumbing Ltd | Construction | 2025 |
| Josan Homes Ltd | Construction | 2024 |
| Jose Vieira Constructions Ltd | Construction | 2025 |
| Joseph & Co Solicitors Ltd | Professional & scientific | 2020 |
| Joseph A.Ball(Printers)Limited | Manufacturing | 1964 |
| Joseph Bera Limited | Wholesale & retail | 2023 |
| Joseph Coleman Ltd | Administrative & support | 2016 |
| Joseph Davies Barbering Ltd | Other services | 2020 |
| Joseph Esther Properties Limited | Real estate | 2025 |
| Joseph Kerrigan Ltd | Information & communication | 2013 |
| Joseph Lowres Limited | Information & communication | 2016 |
| Joseph Solomon Ltd | Professional & scientific | 2018 |
| Joseph Willison Ltd | Construction | 2024 |
| Josephinesdesign Limited | Arts & recreation | 2024 |
| Josewin Limited | Professional & scientific | 2006 |
| Josewin Training and Development Ltd | Administrative & support | 2017 |
| Josh Legg Group Ltd | Administrative & support | 2018 |
| Josh Ventures Ltd | Construction | 2025 |
| Joshi Mortgage & Protection Limited | Financial services | 2024 |
| Joshi Property Holdings Limited | Real estate | 2024 |
| Joshi Tech Ltd | Information & communication | 2021 |
| Joshro Limited | Administrative & support | 2026 |
| Joshua Mowll Limited | Professional & scientific | 2015 |
| Josiah`S Limited | Administrative & support | 2008 |
| Josm Ltd | Real estate | 2023 |
| Joss Moray Limited | Arts & recreation | 2025 |
| JOT Haulage Ltd | Transport & logistics | 2020 |
| Jotterly Ltd | Information & communication | 2026 |
| Jotters Limited | Education | 2008 |
| Jotu Educational Consultant Limited | Education | 2024 |
| Joulton Innovations Ltd | Transport & logistics | 2015 |
| Journalism and Mass Media Academy in London Ltd | Information & communication | 2021 |
| Jovaart Ltd | Manufacturing | 2015 |