| Jmspeed Ltd | Real estate | 2025 |
| JMT Interiors Limited | Wholesale & retail | 2026 |
| JN Andrews Commercial and Agricultural Services Limited | Agriculture & fishing | 2015 |
| JNA Properties (Doncaster) Ltd | Real estate | 2018 |
| Jncafe Ltd | Hospitality | 2025 |
| JNJ Associates Limited | Administrative & support | 2013 |
| JNT Catering Ltd | Hospitality | 2022 |
| JO Webster Coaching & Consultancy Services Ltd | Professional & scientific | 2026 |
| Joanna Siembida Security Ltd | Administrative & support | 2024 |
| Joanne Henry Limited | Professional & scientific | 2022 |
| Jobjob Ltd | Information & communication | 2025 |
| Jock Sergison Garage Limited | Wholesale & retail | 2010 |
| Jodan Property Ltd | Real estate | 2025 |
| Jodi Marie Beauty & Aesthetics Limited | Other services | 2025 |
| Jodi Marie Training Academy Ltd | Education | 2026 |
| Jody Stanton FX Ltd | Arts & recreation | 2023 |
| JOE Lister Combat Sports Ltd | Arts & recreation | 2026 |
| JOE Sharp Physiotherapy Limited | Health & social care | 2014 |
| Joebentaylor Ltd | Information & communication | 2020 |
| Joel Needham TM Ltd | Public administration | 2025 |
| Joelfrei Ltd | Wholesale & retail | 2026 |
| Joem Properties Ltd | Real estate | 2025 |
| Joe’S Pilates Club Limited | Arts & recreation | 2025 |
| Joheem Holding Ltd | Financial services | 2025 |
| John Andrews Precision Engineering Limited | Manufacturing | 2005 |
| John Brailsford Print (Yorkshire) Limited | Manufacturing | 1993 |
| John Broderick Driver Training Ltd | Education | 2016 |
| John Burt Expert Services Ltd | Transport & logistics | 2012 |
| John Clark TM Ltd | Public administration | 2025 |
| John Crabtree Limited | Information & communication | 2010 |
| John Harrison HGV Ltd | Transport & logistics | 2017 |
| John Heir Joinery Ltd | Construction | 2021 |
| John Holt & Sons LLP | | 2015 |
| John Hudson Trailers Ltd | Wholesale & retail | 1975 |
| John Martin Construction Ltd | Construction | 2023 |
| John Mcquater Limited | Education | 2019 |
| John Moon 1943 Limited | Financial services | 2026 |
| John Moon Ltd | Other services | 2024 |
| John Radford Mtfc Stadium Ltd | Arts & recreation | 2012 |
| John Richards Developments (UK) Limited | Construction | 2013 |
| John Sleath Race Cars Limited | Manufacturing | 2003 |
| John Stacey (Electrical Contractors) Limited | Wholesale & retail | 2003 |
| John TE Ltd | Transport & logistics | 2019 |
| John Tully Engineering UK Limited | Construction | 2019 |
| John Wakeman Consultant Ltd | Professional & scientific | 2025 |
| John William Strutt Limited | Extraterritorial | 2014 |
| JOHN316 Ltd. | Financial services | 2009 |
| Johnson & SON Project Management Ltd | Construction | 2025 |
| Johnson Commissioning Services Limited | Energy | 2011 |
| Johnson Property Investments Limited | Real estate | 2024 |
| Johnsons Consultancy Services Ltd | Construction | 2023 |
| Johnsons Drainage Services Limited | Administrative & support | 2017 |
| Johnston Fitout Group UK Limited | Real estate | 2024 |
| Johnston Shopfitters UK Limited | Construction | 2014 |
| Join Creative Ltd | Professional & scientific | 2018 |
| Jokora Group Ltd | Wholesale & retail | 2025 |
| Jolly Ledger Ltd | Extraterritorial | 2026 |
| JON Bailey Developments Limited | Real estate | 2009 |
| Jon-Paul Ltd | Real estate | 2020 |
| Jonas Trans Ltd | Transport & logistics | 2014 |
| Jonathan Davis Financial Consultancy Limited | Financial services | 2002 |
| Jonathan Kirk TM Ltd | Public administration | 2025 |
| Jones & Newsham Limited | Manufacturing | 2013 |
| Jones & SON Associates Ltd | Administrative & support | 2024 |
| Jones Bros Transport Solutions Ltd | Transport & logistics | 2022 |
| Jones Electric (Doncaster) Limited | Construction | 2017 |
| Jones Electrical & Security Ltd | Construction | 2023 |
| Jones Engineering Export Limited | Wholesale & retail | 2010 |
| Jones Engineering Manufacturing Limited | Manufacturing | 2010 |
| Jones Entertainment Limited | Hospitality | 2023 |
| Jones Homestead Ltd | Real estate | 2020 |
| Jones’S Properties Ltd | Real estate | 2026 |
| Jono's Place CIC | Health & social care | 2025 |
| Joojoo Enterprises Limited | Information & communication | 2020 |
| Joosten Real Estate Ltd | Real estate | 2023 |
| Jordanslaw Ltd | Professional & scientific | 2024 |
| JOS Plant Services Ltd | Construction | 2026 |
| Joseph Curle Ltd | Professional & scientific | 2026 |
| Joseph John Thomson Limited | Professional & scientific | 2014 |
| Josephine Accounting Solutions Ltd | Real estate | 2025 |
| Josh Street Coaching Ltd | Arts & recreation | 2022 |
| Joshcecom Limited | Wholesale & retail | 2024 |
| Joshuava Driver Hire Limited | Transport & logistics | 2016 |
| Josh’S Potatoes Ltd | Arts & recreation | 2026 |
| Joss Engineering (Barrow) Ltd. | Professional & scientific | 2019 |
| Journey Education Group Ltd | Education | 2019 |
| Journey Education Tutoring Ltd | Education | 2022 |
| Journey Independent School Ltd | Education | 2026 |
| Journeyman Automation Limited | Construction | 2019 |
| Joy and Beauty Limited | Other services | 2024 |
| Joybe Ltd | Arts & recreation | 2025 |
| Joyce Management Limited | Manufacturing | 2015 |
| Joyfulbirth Ltd | Professional & scientific | 2024 |
| Joying Limited | Real estate | 2026 |
| Joyline MAC Ltd | Health & social care | 2018 |
| Joyous Grace Ltd | Health & social care | 2026 |
| Jozara Accounting Ltd | Professional & scientific | 2020 |
| Jozara Ltd | Other services | 2019 |
| Jozef & Sons Ltd | Construction | 2025 |
| JP & SA Rentals Ltd | Real estate | 2022 |