| J W Timber Trading Limited | Wholesale & retail | 2022 |
| J&B Logistics Consultancy Services Ltd | Information & communication | 2024 |
| J&B Properties (York) Ltd | Real estate | 2023 |
| J&H 721 Limited | Real estate | 2021 |
| J&L Clark Holdings Limited | Real estate | 2021 |
| J&M Parks Limited | Hospitality | 2026 |
| J&M Property (York) Ltd | Real estate | 2022 |
| J&P Properties (Yorkshire) Ltd | Real estate | 2021 |
| J&S Floors Ltd | Professional & scientific | 2010 |
| J&T Property Holdings Ltd | Financial services | 2024 |
| J-Night Ltd | Arts & recreation | 2009 |
| J-Tronics Limited | Wholesale & retail | 1990 |
| J. & J.L.Robinson Farms Ltd | Agriculture & fishing | 2022 |
| J. Illingworth and Company Limited | Financial services | 1972 |
| J. Rotherham Group Ltd | Manufacturing | 2020 |
| J. S. Allison Ltd | Construction | 2008 |
| J.A.B Roofing Ltd | Construction | 2022 |
| J.A.K Marketing Limited | Wholesale & retail | 2001 |
| J.C. Lister Farms Limited | Agriculture & fishing | 1970 |
| J.E.Dawson Ltd | Financial services | 2014 |
| J.E.Hartley Limited | Agriculture & fishing | 1954 |
| J.G. Associates Ltd | Construction | 2006 |
| J.H.Shouksmith & Sons Limited | Construction | 1919 |
| J.K. Hargreaves Investments Limited | Extraterritorial | 2021 |
| J.K.E. Solutions Limited | Information & communication | 2002 |
| J.M Sadler Construction Ltd | Construction | 2025 |
| J.M. Smith (Construction) Limited | Real estate | 1977 |
| J.P Sushi Ltd | Hospitality | 2026 |
| J.P.Swimming Pool Solutions Limited | Construction | 2014 |
| J.S. Woodcraft Limited | Construction | 2011 |
| J.T. Allison & Sons Ltd | Construction | 2019 |
| J.W Preece Limited | Real estate | 2024 |
| J.W. Liptrot & Company Limited | Extraterritorial | 1944 |
| J.Webster (Joinery) Ltd | Construction | 2002 |
| J4VISION Trading Limited | Wholesale & retail | 2023 |
| J6 Holdings Limited | Financial services | 2026 |
| J9 Consultant Services Limited | Information & communication | 2002 |
| JA Property (York) Ltd | Real estate | 2024 |
| JA Tuition Ltd | Education | 2021 |
| Jabbari Properties Ltd | Real estate | 2025 |
| Jabbers’ Everyman Ltd | Construction | 2023 |
| Jaboulet Limited | Extraterritorial | 1972 |
| Jacis of York Ltd | Wholesale & retail | 2020 |
| Jack Buxton Construction Limited | Construction | 2018 |
| Jack Clarke Management Ltd | Arts & recreation | 2019 |
| Jack Huang Ltd | Hospitality | 2018 |
| Jack Marshall Hairdressing Limited | Arts & recreation | 2021 |
| Jack's Bootham Tavern Limited | Hospitality | 2016 |
| Jack's Pocklington Ltd | Hospitality | 2025 |
| Jackdaw Newsletters Limited | Information & communication | 2000 |
| Jackrabbit Yorkshire Ltd | Hospitality | 2025 |
| Jackson Investments Yorkshire Limited | Real estate | 2017 |
| Jacksons Building Components Limited | Manufacturing | 2004 |
| Jacksons Creations Limited | Manufacturing | 2025 |
| Jacobs Court (Clifton) Management Company Limited | Households | 2004 |
| Jacobs Court (York) Management Company Limited | Real estate | 2006 |
| Jacobs Letting Ltd | Real estate | 2021 |
| Jacques Dairies Limited | Wholesale & retail | 2003 |
| Jacques Interiors Ltd | Construction | 2022 |
| Jacques Towbar & Leisure Services Limited | Wholesale & retail | 2019 |
| Jaga Properties Ltd | Construction | 2015 |
| Jago Limited | Wholesale & retail | 2002 |
| JAJ Construction Management Limited | Extraterritorial | 2016 |
| Jako - Trade Ltd | Construction | 2016 |
| Jallow Homes Ltd | Real estate | 2025 |
| JAM Holiday Lets Ltd | Real estate | 2018 |
| JAM Homes Ltd | Real estate | 2014 |
| JAM Lass Investments Limited | Real estate | 2022 |
| JAM Lass Limited | Wholesale & retail | 2022 |
| JAM Lass Racing Limited | Agriculture & fishing | 2022 |
| Jamaka Ltd | Hospitality | 2018 |
| Jamarama Limited | Wholesale & retail | 2025 |
| James Barwell Ltd | Information & communication | 2014 |
| James Bradley Design Ltd | Information & communication | 2018 |
| James Hart Investments Trading AS Headquarters Limited | Other services | 2026 |
| James Holding Dairy Engineering Ltd | Wholesale & retail | 2019 |
| James Horsley Limited | Construction | 2019 |
| James Langdale Ltd | Construction | 2017 |
| James Leech Motorsports Ltd | Administrative & support | 2017 |
| James Lester Ltd | Professional & scientific | 2015 |
| James Milton Apps Ltd | Information & communication | 2025 |
| James Nixon Ltd | Wholesale & retail | 2010 |
| James Primmer Architects Ltd | Professional & scientific | 2024 |
| James Thornton Family Law Limited | Professional & scientific | 2024 |
| Jamesmhoward Ltd | Information & communication | 2019 |
| Jamie Akers Logistics Ltd | Transport & logistics | 2023 |
| Jamie Mcneil Ltd | Wholesale & retail | 2023 |
| Jammed Bookings Limited | Information & communication | 2018 |
| Janasta Ltd | Other services | 2003 |
| Jane Nordli Weddings and Events Planning Ltd | Other services | 2009 |
| Janico of York Limited | Manufacturing | 2014 |
| Janna Spice Ltd | Hospitality | 2018 |
| Janosfutar Ltd | Transport & logistics | 2025 |
| Janus Recruitment Solutions Limited | Administrative & support | 2016 |
| Japp Media Limited | Manufacturing | 2017 |
| Jarvis Post Interiors Limited | Professional & scientific | 2017 |
| Jason Brooks Art Limited | Arts & recreation | 2010 |
| Jason C Boakes | Extraterritorial | 2011 |
| Jason White Ltd | Hospitality | 2017 |
| Jasonq Ltd | Wholesale & retail | 2026 |