| J S Lakhanpal Properties Limited | Real estate | 2020 |
| J S Morrell Ltd | Transport & logistics | 2016 |
| J Steven Green Ltd | Wholesale & retail | 2024 |
| J T S Geotechnical Solutions Limited | Construction | 2013 |
| J Thompson Engineering Services Ltd | Professional & scientific | 2021 |
| J Trade Solo Ltd | Wholesale & retail | 2026 |
| J Walker Scaffolding Ltd | Construction | 2021 |
| J Walker Travel Ltd | Administrative & support | 2024 |
| J Wegner Trading Ltd | Wholesale & retail | 2016 |
| J Willows Brickwork Ltd | Construction | 2026 |
| J&A Haulage Limited | Transport & logistics | 2025 |
| J&H Property Developments Ltd | Construction | 2014 |
| J&I Haulage Ltd | Transport & logistics | 2018 |
| J&J Canines Ltd | Other services | 2022 |
| J&K Property Yorkshire Ltd | Real estate | 2025 |
| J&M Competitions Limited | Wholesale & retail | 2024 |
| J&M Repairs Ltd | Wholesale & retail | 2024 |
| J&N Holdings (Yorkshire) Limited | Wholesale & retail | 2020 |
| J&R Autos (2024) Ltd | Wholesale & retail | 2024 |
| J&R Cars Ltd | Wholesale & retail | 2018 |
| J&R Performance Ltd | Professional & scientific | 2025 |
| J&S Upholstery Ltd | Manufacturing | 2025 |
| J&T Holiday Lets Ltd | Hospitality | 2025 |
| J-A-R Sourcing Ltd | Real estate | 2019 |
| J-Emss Ltd | Public administration | 2016 |
| J-Vis Transport Ltd | Transport & logistics | 2020 |
| J. H Electrical & Solar Ltd | Construction | 2022 |
| J. Housley Building Services Ltd | Construction | 2025 |
| J. M. Holling Limited | Transport & logistics | 1999 |
| J. Marsden Property Limited | Real estate | 2023 |
| J. Milne Commercial Consulting Ltd | Administrative & support | 2022 |
| J.A.& M.G.Firth | | 1991 |
| J.A.N Electrical Ltd | Professional & scientific | 2025 |
| J.A.W. Associates Limited | Construction | 2002 |
| J.Bennett Property Ltd | Real estate | 2023 |
| J.C Highways Ltd | Construction | 2024 |
| J.C. James Investments Limited | Administrative & support | 2022 |
| J.F. Scott and SON (Womersley) Limited | Arts & recreation | 1963 |
| J.H.M.Butt & Co.Limited | Wholesale & retail | 1971 |
| J.Johnson Haulage Ltd | Transport & logistics | 2023 |
| J.K Civils & Drainage Ltd | Construction | 2025 |
| J.L.Burton Services Ltd | Administrative & support | 2024 |
| J.M. Ward Limited | Wholesale & retail | 1937 |
| J.Mcardle Ltd | Transport & logistics | 2025 |
| J.Mcpherson Ltd | Information & communication | 2011 |
| J.P.M. Harrison Transport Limited | Transport & logistics | 2003 |
| J.R. Cockin (Electrical Contractors) Limited | Construction | 1987 |
| J.S Commercial Tyres Limited | Wholesale & retail | 2024 |
| J.V Dutton Contractors Limited | Construction | 2024 |
| J.Vernelen Engineering Limited | Professional & scientific | 2019 |
| J1 Properties Limited | Real estate | 2012 |
| J2DM Limited | Health & social care | 2026 |
| J3 Business Park Doncaster LLP | | 2013 |
| J4 (M18) Properties Ltd | Real estate | 2019 |
| J4 Sand & Gravel Ltd | Mining & quarrying | 2024 |
| J7 Autoservices Limited | Wholesale & retail | 2003 |
| J82 Limited | Administrative & support | 2019 |
| JA & EL Investments Limited | Information & communication | 2018 |
| JA Tordoff & SON Limited | Construction | 2020 |
| Ja's Auto Services Limited | Wholesale & retail | 2006 |
| Jaal Rail Services Limited | Professional & scientific | 2017 |
| JAB Site Services Ltd | Transport & logistics | 2025 |
| Jabrom Fitness Ltd. | Education | 2022 |
| JAC & Associates Limited | Professional & scientific | 2002 |
| JAC Auto PVT Ltd | Wholesale & retail | 2025 |
| JAC Products Limited | Wholesale & retail | 2021 |
| Jacdaw Chesterfield Ltd | Financial services | 2023 |
| Jacdaw Ltd | Hospitality | 2023 |
| Jacek Wojcik Ltd | Transport & logistics | 2020 |
| Jack Barnett TM Ltd | Public administration | 2022 |
| Jack Burgers Ltd | Hospitality | 2019 |
| Jack Mccabe Q. S. Services Limited | Professional & scientific | 2014 |
| Jack Parnaby Ltd | Wholesale & retail | 2026 |
| Jack Shaw TM Ltd | Public administration | 2024 |
| Jack Thomas Limited | Wholesale & retail | 2024 |
| Jack Zahn Ltd | Health & social care | 2024 |
| Jackdaw Wood CIC | Health & social care | 2021 |
| Jacki Pritchard Ltd | Health & social care | 2003 |
| Jackpot Trading Ltd | Manufacturing | 2021 |
| Jackson Carter Wood Management Limited | Manufacturing | 2006 |
| Jackson Holmes Ltd | Real estate | 2024 |
| Jacksons Property Services Ltd | Construction | 2023 |
| Jackwell Properties Ltd | Real estate | 2021 |
| Jackwell Residential Ltd | Real estate | 2026 |
| Jacob PJR Ltd | Transport & logistics | 2019 |
| Jacob Transport Ltd | Transport & logistics | 2015 |
| Jacombs Enterprises Ltd | Extraterritorial | 2020 |
| Jacques Bar Ltd | Hospitality | 2024 |
| Jacron Ltd | Wholesale & retail | 2010 |
| JAD and Jord Healthcare Ltd | Health & social care | 2015 |
| Jade House Doncaster Ltd | Hospitality | 2025 |
| Jade House Takeaway Doncaster Ltd | Hospitality | 2026 |
| Jade Newby Financial Services Limited | Wholesale & retail | 2019 |
| Jadestand Limited | Extraterritorial | 2013 |
| Jadevale Limited | Extraterritorial | 2013 |
| Jadewave Limited | Extraterritorial | 2013 |
| Jadoon Arabia Ltd | Construction | 2024 |
| JAF Enterprises Limited | Wholesale & retail | 2020 |
| Jaffersons Investments Limited | Professional & scientific | 2014 |
| Jaffersons Pharma Limited | Professional & scientific | 2013 |