| Juniper International Ltd | Professional & scientific | 2023 |
| Junpeng Limited | Hospitality | 2022 |
| Juratek Limited | Wholesale & retail | 1982 |
| Just Another Production Company Limited | Information & communication | 2016 |
| Just DIG IT Ltd | Construction | 2024 |
| Just M&E Ltd | Extraterritorial | 2022 |
| Just Married Ltd | Transport & logistics | 2025 |
| Just Roadster Ltd | Wholesale & retail | 2013 |
| Just Servicing Ltd | Wholesale & retail | 2026 |
| Justin Rickell Automotive Limited | Wholesale & retail | 2016 |
| JV Car Detailing Limited | Administrative & support | 2025 |
| Jvautomation Ltd | Professional & scientific | 2026 |
| JVS Consulting Ltd | Information & communication | 2017 |
| JW Auto Services Ltd | Wholesale & retail | 2022 |
| JW Building Solutions Ltd | Construction | 2019 |
| JW Cars Doncaster Ltd | Wholesale & retail | 2023 |
| JWE Properties Limited | Real estate | 2018 |
| Jwga Solutions Ltd | Professional & scientific | 2020 |
| Jwgk Limited | Professional & scientific | 2020 |
| JWP Motors Ltd | Wholesale & retail | 2025 |
| JY Taxis Ltd | Transport & logistics | 2019 |
| JZC Ltd | Real estate | 2020 |
| JZK Logistic Ltd | Transport & logistics | 2021 |
| J’S Cafe & Takeaway Ltd | Wholesale & retail | 2020 |
| K & a Consulting Services Ltd | Professional & scientific | 2026 |
| K & a Transport (Yorkshire) Ltd | Transport & logistics | 2011 |
| K & J H Properties Limited | Real estate | 2026 |
| K & K Properties ( Doncaster) Ltd | Real estate | 2024 |
| K & M Developments (Yorkshire) Ltd | Manufacturing | 2015 |
| K and L Restaurants Ltd | Hospitality | 2020 |
| K Brennan Medical Services Limited | Health & social care | 2004 |
| K Butler Automotive Limited | Wholesale & retail | 2014 |
| K Clarke Practitioner Ltd | Administrative & support | 2016 |
| K Coll Welding Inspection Ltd | Professional & scientific | 2016 |
| K D Davis and Sons (the Greengrocers) Ltd | Wholesale & retail | 2015 |
| K Dixon Funeral Services Limited | Other services | 2020 |
| K E Lunness Limited | Mining & quarrying | 2022 |
| K F Mech Ltd | Construction | 2023 |
| K Fuller Limited | Construction | 2026 |
| K G Doncaster Plumbing Ltd | Construction | 2021 |
| K G L G Holdings Limited | Financial services | 2021 |
| K Green Services Limited | Construction | 2019 |
| K H (Pollington) Ltd | Hospitality | 2017 |
| K Humphries & Sons Roofing Contractors Limited | Construction | 2008 |
| K Janiak Ltd | Transport & logistics | 2023 |
| K Kaminski TM Ltd | Public administration | 2024 |
| K Kitchen Fittings Limited | Construction | 2017 |
| K M Wright Property Ltd | Real estate | 2021 |
| K Pawlowski Ltd | Transport & logistics | 2015 |
| K T Accountancy Ltd | Professional & scientific | 2018 |
| K Thompson Brickwork Limited | Construction | 2022 |
| K Thumma Ltd | Hospitality | 2026 |
| K V (Doncaster) Transport Limited | Wholesale & retail | 2017 |
| K&A Merger Limited | Professional & scientific | 2012 |
| K&C Developments Ltd | Manufacturing | 2020 |
| K&I Consultancy Ltd | Construction | 2022 |
| K&K Construction Solutions Limited | Construction | 2017 |
| K&K Property Group Ltd | Real estate | 2026 |
| K&M Beauty Ltd | Wholesale & retail | 2019 |
| K&M Consultancy Limited | Other services | 2026 |
| K&P Prime Ltd | Wholesale & retail | 2025 |
| K&V Foods Ltd | Wholesale & retail | 2024 |
| K-9 Security Dogs Netherland Ltd | Professional & scientific | 2005 |
| K-Moor Holding Ltd | Wholesale & retail | 2026 |
| K-Nar Ltd | Construction | 2020 |
| K.A.D. Site Serv Limited | Manufacturing | 2014 |
| K.D Custom Ltd | Manufacturing | 2019 |
| K.E.Lunness Aggregates Limited | Wholesale & retail | 1998 |
| K.N.N Property Ltd | Construction | 2025 |
| K.Summers TM Ltd | Construction | 2019 |
| K/S Hollybank Ltd | Real estate | 2024 |
| K24 Ltd | Information & communication | 2024 |
| K4 Construction Limited | Construction | 2023 |
| K8TECHNOLOGY Ltd | Information & communication | 2025 |
| K9 Property Ltd | Real estate | 2026 |
| K9 Warehouse Ltd | Manufacturing | 2025 |
| Kaan Pizza Ltd | Hospitality | 2025 |
| Kacpib Ltd | Transport & logistics | 2025 |
| KAF Logistic Ltd | Transport & logistics | 2021 |
| Kaha Pilates Ltd | Wholesale & retail | 2025 |
| KAI CEM Narin Ltd | Professional & scientific | 2023 |
| KAI Priestley Ltd | Construction | 2026 |
| Kairos Care Services Limited | Public administration | 2022 |
| Kajsa Limited | Professional & scientific | 2014 |
| Kalib Carpenters Ltd | Manufacturing | 2024 |
| Kalitu Ltd | Information & communication | 2024 |
| Kalkut Retail Ltd | Wholesale & retail | 2015 |
| Kall Solutions LLP | | 2022 |
| Kallaur Programme Solutions Ltd | Information & communication | 2010 |
| Kalm Digital Ltd | Information & communication | 2023 |
| Kama Building Services Design Limited | Professional & scientific | 2006 |
| Kambalatransport Ltd | Transport & logistics | 2025 |
| Kambex Limited | Transport & logistics | 2016 |
| Kamej Logistic Ltd | Transport & logistics | 2019 |
| Kamil Global Trans Ltd | Transport & logistics | 2025 |
| Kamil Walinowicz Ltd | Transport & logistics | 2025 |
| Kamilcargo Ltd | Transport & logistics | 2025 |
| Kaminah Enterprises Limited | Financial services | 2006 |
| Kamixx Ltd | Transport & logistics | 2017 |
| Kamka Limited | Hospitality | 2026 |