| JBA Corp Ltd | Health & social care | 2021 |
| JBH Site Services Ltd | Construction | 2019 |
| JBW Environmental Services Ltd | Water & waste | 2025 |
| JCP HR Consulting Ltd | Administrative & support | 2026 |
| JD Beds Limited | Manufacturing | 2026 |
| JD Forestry Limited | Agriculture & fishing | 2019 |
| JD Transport (Batley) Limited | Extraterritorial | 2021 |
| JDP Contracting Ltd | Transport & logistics | 2015 |
| JEM Automation Limited | Professional & scientific | 2019 |
| Jesben Limited | Health & social care | 2024 |
| JF Visuals Ltd | Information & communication | 2025 |
| JJ Electrical Contractors Limited | Construction | 2016 |
| Jjmc Limited | Construction | 2024 |
| Jkmb Holdings Limited | Professional & scientific | 2022 |
| JL GAS Point Ltd | Construction | 2025 |
| JLL Estates Ltd | Real estate | 2021 |
| JLM Contract Services Limited | Construction | 2022 |
| JM Partnership (Surveyors) Limited | Other services | 1997 |
| JM Property Ventures Limited | Real estate | 2018 |
| JMB Electrical Solutions Ltd | Construction | 2017 |
| JMM Timber Engineering Ltd | Manufacturing | 2025 |
| Jodie Telford Limited | Professional & scientific | 2022 |
| Jodiie Louiise Fitness Limited | Arts & recreation | 2026 |
| Jogee Properties Ltd | Real estate | 2015 |
| Johdia Ecommerce Ltd | Wholesale & retail | 2024 |
| Johnny M'S Welding Services Ltd | Construction | 2019 |
| Johnstone's Paints Limited | Professional & scientific | 1922 |
| Jollity Games Limited | Manufacturing | 2024 |
| Joshua Ellis and Company,Limited | Manufacturing | 1900 |
| Joud Accessories Ltd | Wholesale & retail | 2023 |
| Jq's Kitchen & PUB Ltd | Hospitality | 2023 |
| JS Capital Investments Limited | Real estate | 2018 |
| JS Quality Furniture Ltd | Wholesale & retail | 2011 |
| JSC Baltic Maintenance Ltd | Wholesale & retail | 2020 |
| Jubilee Wills & Estate Planning Ltd | Professional & scientific | 2024 |
| Just Move Gyms Ltd | Arts & recreation | 2025 |
| Just One Courier Ltd | Transport & logistics | 2024 |
| JV Engineering Group Limited | Financial services | 2025 |
| JV Systems Limited | Professional & scientific | 2025 |
| K&K Medical Services Ltd | Health & social care | 2008 |
| K.P.Z. Healthcare Ltd. | Wholesale & retail | 2016 |
| K.R.R. Housing Ltd | Real estate | 2023 |
| K2 Recycling Ltd | Wholesale & retail | 2025 |
| Kaams Enterprises Limited | Other services | 2023 |
| KAB Consultants Limited | Wholesale & retail | 2024 |
| Kabuliwala Limited | Hospitality | 2021 |
| Kadir Optical Ltd | Health & social care | 2023 |
| KAI Holdings Group Ltd | Other services | 2025 |
| Kaikou Ltd | Information & communication | 2022 |
| Kaji Group Limited | Wholesale & retail | 2024 |
| Kalon Investment Company Limited | Professional & scientific | 1993 |
| KAM Pharma Ltd | Wholesale & retail | 2020 |
| Kama Logistic Ltd | Administrative & support | 2018 |
| Kamaya Academy Limited | Other services | 2023 |
| Kamaya Beauty & Cosmetics Ltd | Wholesale & retail | 2024 |
| Kamaya Ltd | Wholesale & retail | 2020 |
| Kangaroo Haulage Ltd | Transport & logistics | 2016 |
| Karl Austerfield Roofing Limited | Construction | 2006 |
| Karolia Enterprises Ltd | Financial services | 2024 |
| Karolia Transfers Ltd | Transport & logistics | 2025 |
| Kasana Beds Limited | Manufacturing | 2024 |
| Kashmir Balti Goole Ltd | Hospitality | 2019 |
| KAT Investments Management Europe Ltd | Financial services | 2021 |
| Kawadi Group Ltd | Wholesale & retail | 2025 |
| Kawasaki Autorama Limited | Wholesale & retail | 2012 |
| Kazi Travel Limited | Administrative & support | 2025 |
| KC Fast Food Ltd | Hospitality | 2024 |
| KDM Agency Limited | Professional & scientific | 2017 |
| Kenu Properties Ltd | Real estate | 2024 |
| Keyprint (Leeds) Limited | | 1982 |
| Keystone Haulage Ltd | Transport & logistics | 2026 |
| Keystone Properties Leeds Ltd | Real estate | 2025 |
| KH Electrical Solutions Ltd | Construction | 2025 |
| KH Management Services (Batley) Ltd | Professional & scientific | 2024 |
| KHA Properties Ltd | Households | 2026 |
| Khan Packages Limited | Transport & logistics | 2025 |
| Khan Plumbing & DIY Ltd | Wholesale & retail | 2025 |
| Khanx Brothers Ltd | Wholesale & retail | 2021 |
| Khanz Healthcare Services Limited | Health & social care | 2015 |
| Khuram & Co Distribution Ltd | Transport & logistics | 2025 |
| Khyber KEV Limited | Hospitality | 2024 |
| Khyber Takeaway Limited | Hospitality | 2019 |
| Kingsman Express Holdings LLP | | 2023 |
| Kingswalk Developments Limited | Construction | 2026 |
| Kirklees Limited | Wholesale & retail | 2008 |
| Kixx Oldham 2 Limited | Education | 2023 |
| Kixx Rochdale Limited | Arts & recreation | 2022 |
| KJ Travels Ltd | Transport & logistics | 2026 |
| KL Accomodation Ltd | Real estate | 2025 |
| Knightsbridge Bedding Ltd | Wholesale & retail | 2026 |
| KNR Business Services Limited | Administrative & support | 2021 |
| Kola Enterprises Ltd | Wholesale & retail | 2017 |
| Kolowagg AD Ltd | Construction | 2021 |
| Kontrast Antiques & Interiors Ltd | Wholesale & retail | 2024 |
| Koobz Limited | Wholesale & retail | 2023 |
| Kotia Ltd | Professional & scientific | 2015 |
| Koyla Ltd | Hospitality | 2024 |
| KPL Properties (Yorkshire) Limited | Other services | 2025 |
| KQ Pharma Ltd | Wholesale & retail | 2023 |
| Krystal Accounting Ltd | Professional & scientific | 2023 |