| JESS1E Ltd | Extraterritorial | 2020 |
| JET Aire (DC) Limited | Water & waste | 1997 |
| JET FM Limited | Extraterritorial | 2025 |
| JET Propel Limited | Professional & scientific | 2022 |
| Jetjap Ltd | Construction | 2013 |
| Jeverett Consultancy Limited | Health & social care | 2013 |
| Jewelsinbox Ltd | Wholesale & retail | 2025 |
| JF Interim Ltd | Public administration | 2018 |
| JFP Estates Limited | Construction | 2026 |
| Jgfm Ltd | Construction | 2025 |
| JGT Global Executive Search Limited | Administrative & support | 2020 |
| JH Landscapes York Ltd | Administrative & support | 2025 |
| JH SPV1 Limited | Financial services | 2026 |
| JHH Builders Limited | Construction | 2021 |
| Jhjw Group Limited | Financial services | 2025 |
| JHK Devonshire Ltd | Real estate | 1994 |
| JHK NPI Ltd | Real estate | 2021 |
| JIB Insurance Brokers Limited | Financial services | 2007 |
| Jiffi Ltd | Professional & scientific | 2025 |
| Jist Agency Limited | Information & communication | 2016 |
| JJ Aviation Solutions Limited | Professional & scientific | 2019 |
| JJG Developments Limited | Construction | 2015 |
| JJJ Developments Limited | Construction | 2026 |
| JJM Yorkshire Limited | Real estate | 2024 |
| JK Kingsley Ltd | Real estate | 2021 |
| JK Retail Ltd | Wholesale & retail | 2021 |
| JK Wood Holdings Ltd | Financial services | 2026 |
| JK Wood Ltd | Real estate | 2025 |
| JKP (Yorkshire) Ltd | Professional & scientific | 2015 |
| JKY Limited | Professional & scientific | 2018 |
| JL Management Solutions Ltd | Professional & scientific | 2019 |
| JLR Ltd | Information & communication | 2023 |
| JLS Properties (Leeds) LLP | | 2014 |
| JM Legacy Ltd | Education | 2020 |
| Jmms Holdings Ltd | Real estate | 2019 |
| Jmpm Consulting Ltd | Professional & scientific | 2025 |
| JMS in Edutech Ltd | Information & communication | 2024 |
| Jmund Ltd | Real estate | 2025 |
| Jnko&Co Ltd | Professional & scientific | 2022 |
| JNL Hospitality Ltd | Hospitality | 2022 |
| JNV Investors Ltd | Real estate | 2025 |
| JO3L Ltd | Extraterritorial | 2017 |
| Joana Bridal Boutique Limited | Wholesale & retail | 2020 |
| Jockey Lane Training Limited | Information & communication | 2016 |
| JOD1E Limited | Extraterritorial | 2020 |
| Jodhpur (Harrogate) Limited | Hospitality | 2024 |
| Jodhpur Canteen Limited | Hospitality | 2026 |
| JOE Thom Sound Design Limited | Professional & scientific | 2021 |
| Joel Benjamin Limited | Extraterritorial | 2021 |
| Joel FM Ltd | Extraterritorial | 2015 |
| Joellaro Limited | Real estate | 2026 |
| John Bull Military Clothing Limited | Wholesale & retail | 2020 |
| John Eckart Photography Limited | Professional & scientific | 2004 |
| John Haresign Limited | Construction | 2013 |
| John Hart Limited | Agriculture & fishing | 2012 |
| John Jarvis Consulting Limited | Professional & scientific | 2011 |
| John Reid Professional Services Limited | Professional & scientific | 2013 |
| John Robson Chimney Sweep Ltd | Administrative & support | 2026 |
| John Shackleton & Co Ltd | Professional & scientific | 2003 |
| John Waddington Building Contractors Limited | Professional & scientific | 1998 |
| John Willis Properties Limited | Hospitality | 1999 |
| Johnny Garlics Ltd | Extraterritorial | 2012 |
| Johnson Family Properties Ltd | Real estate | 2026 |
| Johnsons Manufacturing Ltd | Wholesale & retail | 2016 |
| Johnstone Insurance Brokers Limited | Financial services | 2006 |
| Joie DE Vivre Productions Ltd | Information & communication | 2025 |
| Joleon Limited | Wholesale & retail | 2023 |
| Joleon Systems Limited | Extraterritorial | 2026 |
| Jomar Developments NO 1 Limited | Construction | 2016 |
| Jomu Compliance Limited | Administrative & support | 2016 |
| Jomu Properties Limited | Real estate | 2021 |
| Jonal Limited | Professional & scientific | 2005 |
| Jonat Consulting Limited | Real estate | 2011 |
| Jonathan Nixon Ltd | Other services | 2010 |
| Jonathan Peasgood Associates Limited | Real estate | 2015 |
| Jonathan Whitaker - Principal Forensics Ltd | Professional & scientific | 2012 |
| Jones & Partners Financial Planning Ltd | Financial services | 2014 |
| Jones Law Limited | Professional & scientific | 2009 |
| JONN1E Limited | Extraterritorial | 2020 |
| Jons Physio & Acupuncture Ltd | Health & social care | 2024 |
| Jood Almadina Group for Trade Ltd | Hospitality | 2021 |
| Joondanna Consulting and Training Services Limited | Information & communication | 2015 |
| Jordan FM Limited | Extraterritorial | 2025 |
| Jorvik Environmental Consulting Limited | Professional & scientific | 2023 |
| Joseph Hayton Sculptor Ltd | Arts & recreation | 2024 |
| Joshua Mulandi Ltd | Extraterritorial | 2023 |
| Joshua Stephens Golf Limited | Arts & recreation | 2025 |
| Josie Limited | Households | 1980 |
| Josie Rose Skincare Ltd | Wholesale & retail | 2019 |
| Journeys of Discovery UK Limited | Information & communication | 2022 |
| Joyce Brewco Limited | Manufacturing | 2019 |
| JP Aviation Consultancy Ltd | Professional & scientific | 2023 |
| JP Concierge Service Limited | Other services | 2024 |
| JP Detailing Limited | Wholesale & retail | 2017 |
| JP Golf (Harrogate) Limited | Arts & recreation | 2023 |
| JP Joinery & Construction (Yorkshire) Limited | Construction | 2026 |
| JP3 QS Ltd | Professional & scientific | 2020 |
| Jpcooper Properties Ltd | Real estate | 2017 |
| JPD Code Developments Ltd | Information & communication | 2016 |
| JPI Limited | Real estate | 2009 |