| Jobs Butler Ltd | Other services | 2018 |
| Joda Property Group Ltd | Real estate | 2024 |
| John Good & Sons Limited | Professional & scientific | 1908 |
| John Mcintyre Music Limited | Information & communication | 2018 |
| Jovan Holdings Limited | Information & communication | 2020 |
| JP Plumbing and GAS Solutions Ltd | Construction | 2023 |
| JSJ Consultancy Limited | Administrative & support | 2007 |
| JSJ Homes Limited | Construction | 2011 |
| JSJ Partnership Limited | Professional & scientific | 2008 |
| JSR Pyramid Limited | Agriculture & fishing | 2019 |
| Jubilee Developments (NE) Limited | Professional & scientific | 2007 |
| Judgeland Properties Limited | Real estate | 2017 |
| Judgeland Systems Limited | Information & communication | 2003 |
| Julian Property Group Ltd | Real estate | 2025 |
| Jupiter IT Solutions Limited | Information & communication | 2007 |
| Just Design Stuff Limited | Professional & scientific | 2022 |
| Just for Kids at Minster Limited | Education | 2008 |
| JXG Wealth Limited | Financial services | 1992 |
| K & S Allbones (Civil Engineers) Limited | Construction | 1988 |
| K.B. Insulation Limited | Construction | 2006 |
| Kake Roks Limited | Manufacturing | 2021 |
| Karella Limited | Professional & scientific | 2013 |
| Kari Retail Ltd | Wholesale & retail | 2025 |
| Karmer Properties Ltd | Real estate | 2024 |
| Katsouris Brothers Limited | Wholesale & retail | 1964 |
| KC Mortgages Ltd | Financial services | 2024 |
| KC Property Yorkshire Ltd | Real estate | 2024 |
| Kdhatt Consulting Limited | Professional & scientific | 2025 |
| Keenan Consultants Ltd | Information & communication | 2014 |
| Keith Shelley Limited | Construction | 2003 |
| Kelisdar Holiday Lets Limited | Hospitality | 2021 |
| Kemp and Townsend Limited | Construction | 2020 |
| Kencraft Ltd | Construction | 2022 |
| Kennett Insurance Brokers Limited | Financial services | 1975 |
| Kerry Lenney Property Limited | Real estate | 2019 |
| Kettbest Limited | Households | 2002 |
| Keys Scaffolding Limited | Construction | 2007 |
| KF Management (Hull) Limited | Real estate | 2023 |
| Khammar Holdings Limited | Construction | 2017 |
| KHC Hull Properties Limited | Real estate | 2026 |
| Kieldamo Core Heart Ltd | Professional & scientific | 2026 |
| Kingston Capital Finance Limited | Financial services | 2015 |
| Kingston Worldwide Carriers Limited | Transport & logistics | 2009 |
| Kirkwood Landscapes Ltd | Administrative & support | 2024 |
| KJL Education Ltd | Education | 2017 |
| KJL Hessle Ltd | Real estate | 2020 |
| KJM by Kennedy JAI Ltd | Other services | 2024 |
| KK Property Ltd | Real estate | 2026 |
| Kkrn Ltd | Hospitality | 2023 |
| Klejnot DOC Limited | Health & social care | 2016 |
| KLM Hair Studio Limited | Other services | 2011 |
| KM PA Services Ltd | Administrative & support | 2024 |
| Knight Heating Solutions Ltd | Construction | 2026 |
| Knowblee Technology Ltd | Information & communication | 2025 |
| Konsume Ltd | Wholesale & retail | 2024 |
| Krishan (Yorkshire) Limited | Health & social care | 2016 |
| Krishan Properties Limited | Real estate | 2024 |
| Krishna Chauhan Therapy Limited | Health & social care | 2025 |
| KRW SAP Solutions Ltd | Information & communication | 2018 |
| KTS Caistor Limited | Real estate | 2025 |
| KTS Hemswell Limited | Real estate | 2025 |
| Kudos Freight Limited | Transport & logistics | 2017 |
| Kuro Neko Media Ltd | Information & communication | 2025 |
| KVH Holdings Ltd | Real estate | 2026 |
| KW & GW Investments Limited | Construction | 1998 |
| L & R Building Services Ltd | Construction | 2025 |
| L&M Palin Ltd | Professional & scientific | 2024 |
| L.E. Projects Ltd | Construction | 2024 |
| LA Cleche Ltd | Other services | 2019 |
| Labserve (C & M) Limited | Extraterritorial | 2025 |
| LAD Trading Ltd | Manufacturing | 2020 |
| Lakehill Estates Limited | Real estate | 2003 |
| Lakshminarayan Ltd | Health & social care | 2021 |
| Lambert Cole Ltd | Administrative & support | 2015 |
| Land of Green Ginger Limited | Financial services | 2022 |
| Landholding Limited | Financial services | 2006 |
| Last Minute Best Minute Ltd | Information & communication | 2026 |
| Latus Developments Limited | Construction | 2008 |
| Latus Properties Limited | Real estate | 2019 |
| Laurels Lettings Ltd | Real estate | 2012 |
| Lava Socials Limited | Professional & scientific | 2023 |
| Lawrance Commissioning Limited | Administrative & support | 2015 |
| LBJ Fishing (Hull) Limited | Agriculture & fishing | 2006 |
| Leading Digital Associates Ltd | Information & communication | 2019 |
| Learning and Development Consortium Limited | Professional & scientific | 2012 |
| Learning Skills Partnership Ltd | Education | 2010 |
| Leeds Building and Tiling Co Ltd | Construction | 2016 |
| Leeh Limited | Construction | 2018 |
| Legacy Elite Performance Limited | Arts & recreation | 2016 |
| Leisurama Entertainments Limited | Professional & scientific | 1992 |
| Leisurama Holdings Limited | Financial services | 1984 |
| Lemon Clean Limited | Administrative & support | 2009 |
| Lemon Kitchen Mobile Ltd | Hospitality | 2020 |
| Lemon Lifestyle Limited | Other services | 2025 |
| Lemon Marketing Ltd | Administrative & support | 2023 |
| Lemongrass GC Ltd | Hospitality | 2020 |
| LEN Peterson and SON Limited | Administrative & support | 2006 |
| Lenexa Limited | Information & communication | 2026 |
| LET the Games Begin UK Ltd | Arts & recreation | 2022 |
| Lettly Ltd | Information & communication | 2026 |