| J E Hosfield Ltd | Professional & scientific | 2020 |
| J Kirk Ltd | Agriculture & fishing | 2012 |
| J M KAY Electrical Ltd | Construction | 2001 |
| J Pyper Investments Ltd | Real estate | 2019 |
| J R Lister Limited | Professional & scientific | 2010 |
| J Redman Consulting Ltd | Professional & scientific | 2024 |
| J&G ALL Seasons Limited | Hospitality | 2020 |
| J&N Products Ltd | Wholesale & retail | 2016 |
| J. & E. Medcalf Limited | Agriculture & fishing | 1964 |
| J. Akers Ltd | Professional & scientific | 2003 |
| J.F. Designs (Wetherby) Limited | Wholesale & retail | 1990 |
| Jaboh Limited | Health & social care | 2018 |
| Jacd Limited | Professional & scientific | 2019 |
| Jack Gomersall Properties Limited | Real estate | 2015 |
| Jack Joy Insurance Ltd. | Financial services | 2010 |
| Jackdaw Four Ltd | Professional & scientific | 2022 |
| Jacqueline & Edward Ltd | Manufacturing | 2019 |
| Jallyfrey Taverns Limited | Hospitality | 2025 |
| JAM Property & Lettings Ltd | Real estate | 2025 |
| James Crawley Consulting Limited | Extraterritorial | 2025 |
| James King Letting Limited | Real estate | 2004 |
| Jared Lodge Ltd | Professional & scientific | 2008 |
| Jasmine Inns Ltd | Hospitality | 2025 |
| Jaych Entertainment Ltd | Hospitality | 2025 |
| Jaytee (Northallerton) Ltd | Real estate | 2012 |
| Jaytee F&B Ltd | Hospitality | 1997 |
| Jazznation Ltd | Hospitality | 2024 |
| JBU Consultancy Limited | Professional & scientific | 2025 |
| JCM Motor Company Limited | Wholesale & retail | 2014 |
| JD Geoconsultancy Limited | Mining & quarrying | 2024 |
| JDH Medical Limited | Education | 2016 |
| JDM Shopfitters Ltd | Construction | 2014 |
| Jeenie Solutions Ltd | Manufacturing | 2024 |
| Jelly Room Limited | Professional & scientific | 2004 |
| JEM Tiling & Bathrooms Ltd | Construction | 2014 |
| Jenson Green Ltd | Administrative & support | 2020 |
| Jetlife Cases Limited | Manufacturing | 2018 |
| Jets NCL Limited | Professional & scientific | 2024 |
| Jfdi Creative Solutions Limited | Administrative & support | 2019 |
| JG Units Ltd | Real estate | 2026 |
| Jias Limited | Health & social care | 2009 |
| Jimjen Holdings Ltd | Financial services | 2025 |
| Jitc Consulting Limited | Information & communication | 2014 |
| JJ Optical Services Ltd | Wholesale & retail | 2018 |
| Jj&J Property Limited | Real estate | 2022 |
| Jjmw Business Advisory Limited | Administrative & support | 2014 |
| JKT Architecture Ltd | Professional & scientific | 2021 |
| JKW Consultants Ltd | Professional & scientific | 2015 |
| JLB Cyber Ltd | Professional & scientific | 2023 |
| JLS International Limited | Construction | 2000 |
| JM Solutions Engineering Limited | Professional & scientific | 2022 |
| Jmaa Ltd | Other services | 2026 |
| Jmcd Investments Limited | Financial services | 2014 |
| JMD Developments (UK) Limited | Construction | 2002 |
| JMD Group (UK) Limited | Construction | 2007 |
| JMD Rail Limited | Construction | 2007 |
| JMR Education Investments Limited | Financial services | 2024 |
| JO Pallan JP Limited | Extraterritorial | 2024 |
| JO Pope Limited | Professional & scientific | 2025 |
| JO Warner Consulting Limited | Professional & scientific | 2024 |
| Joana Esteves Limited | Wholesale & retail | 2017 |
| JOB More 4 U Ltd | Administrative & support | 2026 |
| John Queripel Associates Investments Limited | Financial services | 2022 |
| Johnston & Johnston Properties Ltd | Real estate | 2019 |
| Jolliffe Hepburn Aviation Ltd. | Transport & logistics | 2013 |
| JON Church Communications Ltd | Professional & scientific | 2020 |
| Jones Security Enterprises Ltd | Administrative & support | 2026 |
| Jonesy Corp Ltd | Administrative & support | 2023 |
| Joseph Ferraro Hair Limited | Other services | 2014 |
| Joseph Ferraro Properties Limited | Real estate | 2023 |
| Joseph Kaye LLP | | 2016 |
| Joshua Pilling Ophthalmology Ltd | Health & social care | 2021 |
| Joshua Taylor & Co Limited | Real estate | 1896 |
| Joyride Partners Limited | Professional & scientific | 2026 |
| JP Automotive (Yorkshire) Ltd | Wholesale & retail | 2023 |
| JP Professional Projects Ltd | Professional & scientific | 2023 |
| JQA Holdings Limited | Financial services | 2024 |
| Jrnbs Limited | Professional & scientific | 2017 |
| JRZ Ltd | Real estate | 2022 |
| JS Accounting Support Ltd | Administrative & support | 2022 |
| JS Customs Ltd | Wholesale & retail | 2020 |
| Judes Kitchen Ltd | Hospitality | 2014 |
| Julian Marshall Contracts Limited | Construction | 2025 |
| July Holdings Ltd | Manufacturing | 2019 |
| Just 'ERE FOT Treats Limited | Wholesale & retail | 2023 |
| Just for FUN Theatre Group Limited | Arts & recreation | 2017 |
| K J Randall and Associates Limited | Professional & scientific | 2013 |
| K&K Brickwork Contractors Limited | Construction | 2014 |
| K8-CONSULTING Limited | Professional & scientific | 2022 |
| Kairos (UK) Limited | Information & communication | 2014 |
| Kanyu Escape Limited | Arts & recreation | 2010 |
| Kapitex Healthcare Limited | Manufacturing | 1990 |
| Kasc Ltd | Hospitality | 2019 |
| Kate Abbey Limited | Professional & scientific | 2012 |
| Kate Barnett Psychology Ltd | Education | 2024 |
| Kearby Development Projects Limited | Real estate | 2012 |
| Keepsake Construction Limited | Construction | 2008 |
| Kelly Welding Services Limited | Manufacturing | 2017 |
| Kelly's Profiles Ltd | Manufacturing | 2020 |
| Kendall-Smith Associates Limited | Professional & scientific | 2012 |