| Interior Stone Property Ltd | Real estate | 2024 |
| Internetsales Limited | Wholesale & retail | 2017 |
| Ionic Purification Limited | Professional & scientific | 2025 |
| Iris Embedded Design Ltd | Professional & scientific | 2020 |
| Ispc Ltd | Information & communication | 2025 |
| It's a Dog's Life, Daycare and Grooming Limited | Arts & recreation | 2018 |
| Italia Autosport Limited | Wholesale & retail | 2025 |
| Iwondergroup Ltd | Arts & recreation | 2015 |
| J Wittos Limited | Hospitality | 2007 |
| J & R Hawkswell Ltd | Health & social care | 2022 |
| J & R Lettings and Property Management Limited | Real estate | 2019 |
| J a W Engineering Limited | Manufacturing | 2001 |
| J B & SON Services (Yorkshire) Limited | Manufacturing | 2014 |
| J L O'Toole Limited | Construction | 2008 |
| J Longbottom Roofing and Building Ltd | Construction | 2024 |
| J M J Sycamore Limited | Professional & scientific | 2010 |
| J M Wood Consulting Ltd | Hospitality | 2024 |
| J Montgomery Limited | Information & communication | 2017 |
| J P Mcdonagh Construction Limited | Construction | 2016 |
| J P Stone Sales Limited | Mining & quarrying | 2022 |
| J Walker Construction Ltd | Construction | 2007 |
| J&Ca Ltd | Professional & scientific | 2009 |
| J&E Dickinson Company | Other services | 2024 |
| J. & J.W. Longbottom Limited | Manufacturing | 1919 |
| Ja-Ke Kitchenware Ltd | Wholesale & retail | 2025 |
| Jackson Project Development Limited | Construction | 2023 |
| Jackson Property Estates Limited | Real estate | 2025 |
| Jackson View Ltd | Other services | 2025 |
| Jagger Lane Development Ltd | Construction | 2026 |
| James Dalton Consultants Limited | Professional & scientific | 2011 |
| James Edwards Project Services Ltd | Professional & scientific | 2020 |
| James Tudor Limited | Professional & scientific | 1995 |
| Jammed BHB Limited | Hospitality | 2026 |
| Jamones Exquisitos Limited | Financial services | 2012 |
| Jazz in Britain Ltd | Information & communication | 2019 |
| JBW Construction Ltd | Construction | 2023 |
| JD Flea and Sons Ltd | Wholesale & retail | 2020 |
| JDW Interiors Ltd | Wholesale & retail | 2013 |
| Jellies Nursery & Preschool Edgerton Ltd | Health & social care | 2026 |
| Jellies Nursery & Preschool Meltham Ltd | Health & social care | 2023 |
| Jellies OUT of School and Holiday Club Limited | Other services | 2011 |
| Jennard Investments Limited | Financial services | 2013 |
| Jessop Fold Management Company Limited | Professional & scientific | 2001 |
| Jetclean Yorkshire Limited | Administrative & support | 2019 |
| Jetwash Direct Limited | Wholesale & retail | 2004 |
| JFN Consultancy Limited | Administrative & support | 2012 |
| Jheel Holmfirth Ltd | Hospitality | 2026 |
| Jimmys Social & Healthcare Services Ltd | Health & social care | 2023 |
| JLF T&D Solutions Ltd | Professional & scientific | 2026 |
| JLG Compliance Ltd | Professional & scientific | 2022 |
| JM & B Properties Limited | Administrative & support | 2012 |
| JMA Technical Solutions Limited | Administrative & support | 2026 |
| Jmbb Properties Limited | Real estate | 2020 |
| JMG Interim Ltd | Professional & scientific | 2026 |
| JMR IFA Ltd | Financial services | 2024 |
| JN Properties Holmfirth Limited | Hospitality | 2018 |
| JO Civils Ltd | Construction | 2026 |
| John Atkinson Ltd | Construction | 2016 |
| John Christopher Hampshaw Limited | Extraterritorial | 2022 |
| Joint Approach Health and Education Ltd | Health & social care | 2015 |
| Joisol Limited | Real estate | 2025 |
| Jonty Wilde Photography Limited | Professional & scientific | 2009 |
| Jordan's Leisure Vehicle Repairs Limited | Manufacturing | 2023 |
| Joseph Whitworth & Co Limited | Professional & scientific | 2024 |
| JPA Motor Company Limited | Wholesale & retail | 2013 |
| JS Key Holdings Limited | Financial services | 2019 |
| JS Plates Ltd | Wholesale & retail | 2025 |
| JSH Homes and Developments Limited | Construction | 2023 |
| JSP Installations Limited | Construction | 2006 |
| JT Fire Safety Consultants Limited | Public administration | 2020 |
| JTA Property Group Ltd | Real estate | 2025 |
| JTD Building Supplies Limited | Wholesale & retail | 2009 |
| JTD Property Limited | Real estate | 2017 |
| JTE Consulting Ltd | Professional & scientific | 2014 |
| Jubb Construction Ltd | Construction | 2024 |
| Juice Learning Limited | Professional & scientific | 2009 |
| Julie Darlington Consulting Limited | Professional & scientific | 2024 |
| Junction Park Management Services Limited | Professional & scientific | 1999 |
| Juniper Sanderson Holdings Limited | Financial services | 2022 |
| Just Caravan Parts Ltd | Wholesale & retail | 2017 |
| Just Hoop CIC | Arts & recreation | 2023 |
| JVA Home Interior Ltd | Wholesale & retail | 2025 |
| JVA Marketing Ltd | Professional & scientific | 2019 |
| JW Building Ltd | Administrative & support | 2026 |
| JWS Contract Services Ltd | Professional & scientific | 2008 |
| K & G Citrine Ltd | Hospitality | 2016 |
| K & T Consultancy Ltd | Financial services | 2011 |
| K B (Huddersfield) Installations Limited | Construction | 2003 |
| K D Technical Consultants Limited | Professional & scientific | 2003 |
| K G Auto Engineer Limited | Wholesale & retail | 2009 |
| K P S Food & Wine Ltd | Wholesale & retail | 2024 |
| K&K Cleaning Services Ltd | Other services | 2019 |
| K9 Pet Store & More Ltd | Wholesale & retail | 2026 |
| K9 Walkies Time LLP | | 2020 |
| Kaigo Ltd | Health & social care | 2024 |
| Kanan Investment Co Limited | Extraterritorial | 2016 |
| Kapeva Limited | Professional & scientific | 2010 |
| Karen Hodges Consulting Limited | Administrative & support | 2025 |
| Kastix House Limited | Wholesale & retail | 2020 |
| Katie Robinson Ltd | Professional & scientific | 2018 |