| John Brown and Daughter Funeral Services Limited | Other services | 2024 |
| John Chapman Fitness Ltd | Education | 2025 |
| John Clayden Lubricants Limited | Wholesale & retail | 2017 |
| John Cohen Sound Ltd | Arts & recreation | 2024 |
| John Coldham Limited | Wholesale & retail | 1973 |
| John Cole Farms (Holdings) | Professional & scientific | 1988 |
| John Cole Farms Limited | Agriculture & fishing | 1987 |
| John E Stevens Ltd | Wholesale & retail | 2015 |
| John F. Howard & Co. Limited | Construction | 1980 |
| John Faircloth Ltd | Wholesale & retail | 2002 |
| John Florence Limited | Health & social care | 1971 |
| John Gordon Wines Limited | Hospitality | 1979 |
| John Hilditch (Builders) Limited | Construction | 1978 |
| John Hurrell & Sons Limited | Manufacturing | 2012 |
| John Innes Bioprospects Limited | Construction | 1999 |
| John Innes Centre | Professional & scientific | 1952 |
| John Innes Foundation | Education | 2005 |
| John Investments Limited | Professional & scientific | 1980 |
| John Jenkins Architectural Designs Limited | Professional & scientific | 2006 |
| John Kemp Holdings Limited | Financial services | 2019 |
| John Kemp Limited | Wholesale & retail | 2002 |
| John Kemp Service Limited | Wholesale & retail | 2012 |
| John Keys Medical Ltd | Health & social care | 2010 |
| John Knight (Quality Cars) Limited | Wholesale & retail | 2003 |
| John Lambert Limited | Wholesale & retail | 2003 |
| John Long Planning Ltd | Professional & scientific | 2018 |
| John Mills Property Holdings Ltd | Real estate | 2025 |
| John Moroney Limited | Construction | 2005 |
| John Oliver (Norwich) Ltd | Other services | 2012 |
| John Oliver Academy Ltd | Education | 2017 |
| John Olivers (Ipswich) Limited | Other services | 2008 |
| John Olivers (Woodbridge) Limited | Other services | 2008 |
| John Osborne Consultancy Limited | Professional & scientific | 2007 |
| John Plummer Holdings Ltd | Real estate | 2016 |
| John Plummer Structural Engineering Ltd | Professional & scientific | 2012 |
| John Russen Builder Ltd | Construction | 2012 |
| John Sadler Plumbing & Heating Ltd | Construction | 2015 |
| John Stephenson Court 'a' & 'B' RTM Company Limited | Households | 2013 |
| John W. Doubleday Limited | Wholesale & retail | 1992 |
| John Woodhouse Joinery Ltd | Construction | 2012 |
| John Youngs Insurance Services Limited | Professional & scientific | 2001 |
| John Youngs Limited | Construction | 1914 |
| Johnny Jaffacake Limited | Arts & recreation | 2026 |
| Johnson and Johnson Limited | Other services | 2025 |
| Johnson Court Limited | Administrative & support | 2007 |
| Johnston Family Trading Ltd | Financial services | 2025 |
| Joint Initiative Physiotherapy Ltd | Health & social care | 2025 |
| Joint Motivation Limited | Health & social care | 2009 |
| JOK Ltd | Professional & scientific | 2022 |
| Jolly Brightwell Ltd | Agriculture & fishing | 1994 |
| Jolly Developments Limited | Construction | 2025 |
| Jolly Gardeners Court Management Association Limited | Households | 1983 |
| Jolly Gymnastics Limited | Education | 2023 |
| Jolly House Limited | Real estate | 2004 |
| Jolly Lobster Interactive Ltd | Information & communication | 2024 |
| Jolly Nest Limited | Wholesale & retail | 2025 |
| Jolly.Cm Ltd | Wholesale & retail | 2024 |
| Jomalyn Ltd | Health & social care | 2016 |
| JON Boon Architects Ltd | Professional & scientific | 2019 |
| JON Kirk Consultancy Limited | Professional & scientific | 2008 |
| JON P Watson Services Limited | Other services | 2018 |
| Jonathan Bacon Limited | Construction | 2021 |
| Jonathan Barrett Limited | Wholesale & retail | 2003 |
| Jonathan Cambridge Limited | Professional & scientific | 2021 |
| Jonathan Hartley Associates Limited | Professional & scientific | 2017 |
| Jonathan Hartley Properties Limited | Real estate | 2020 |
| Jonathan Perkins Limited | Health & social care | 2013 |
| Jonathan Robin Tuck Ltd | Extraterritorial | 2022 |
| Jonathan Stewart Associates Limited | Other services | 2014 |
| Jonathan Wyatt Big Band Ltd | Information & communication | 2017 |
| Jones & Co Lettings Ltd | Real estate | 2016 |
| Jones & Co Property Holdings Ltd | Real estate | 2016 |
| Jones Country Estates Ltd | Financial services | 2023 |
| Jones Country Homes Ltd | Construction | 2023 |
| Jones Distribution Services Ltd | Energy | 2014 |
| Jones Financial (Norwich) Limited | Financial services | 2014 |
| Jones Kemp Limited | Administrative & support | 2005 |
| Jonesy's Brick Shack Ltd | Wholesale & retail | 2026 |
| Jonny Bradley Ltd | Education | 2018 |
| Jonny Catering Ltd | Hospitality | 2026 |
| Joolia Gilvey Limited | Health & social care | 2021 |
| Jordan Brothers Limited | Real estate | 2015 |
| Jordan Care Services Ltd | Health & social care | 2026 |
| Jordan Dean Limited | Construction | 2018 |
| Jordan Developments (East Anglia) Limited | Construction | 2003 |
| Jordan Fencing Limited | Construction | 2009 |
| Jordan Group Holdings Limited | Financial services | 2023 |
| Jose Co Limited | Real estate | 2022 |
| Joseph a D Wright Ltd | Agriculture & fishing | 2019 |
| Joseph Coope Ltd | Information & communication | 2026 |
| Joseph King (Norfolk) Co-Ordination Limited | Financial services | 1970 |
| Joseph King Holdings Limited | Professional & scientific | 1970 |
| Joseph King Properties Limited | Real estate | 2012 |
| Joseph Lancaster Management Company Limited | Households | 2004 |
| Josephine Luke Ltd | Hospitality | 2014 |
| Josh Holman Triathlon Ltd | Other services | 2020 |
| Josh Hoskins Ltd | Wholesale & retail | 2025 |
| Joshtroy Services Limited | Health & social care | 2016 |
| Joshua Healthcare Strategies Ltd | Professional & scientific | 2023 |
| Joslashes Ltd | Other services | 2024 |