| Jaro Jaro Limited | Hospitality | 2017 |
| JAX Group Ltd | Construction | 2022 |
| Jaynn Ltd | Health & social care | 2016 |
| JB Pitts Property Limited | Real estate | 2025 |
| Jblm Consultancy Limited | Professional & scientific | 2016 |
| JD Mulligan Roofing Ltd | Construction | 2022 |
| JD Wilson Holdings Ltd | Professional & scientific | 2026 |
| Jdzk Limited | Real estate | 2022 |
| JET Transport (JT) Ltd | Transport & logistics | 2020 |
| Jewelbuild Consulting Limited | Professional & scientific | 2020 |
| Jewelbuild Limited | Real estate | 2014 |
| JFD Investments Ltd | Extraterritorial | 2018 |
| JIM Jams 4U Limited | Wholesale & retail | 2014 |
| JJ Bespoke Print Ltd | Manufacturing | 2026 |
| JJ Hospitality (Yorkshire) Ltd | Hospitality | 2021 |
| JJW Trading Limited | Wholesale & retail | 2013 |
| JLI Supplies Ltd | Wholesale & retail | 2025 |
| JMH Alloy Wheel Solutions Limited | Wholesale & retail | 2024 |
| JMS Supplies Ltd | Wholesale & retail | 2024 |
| JO Beeley Ltd | Health & social care | 2023 |
| John Henderson UK Limited | Administrative & support | 2001 |
| John Monaghan (Holdings) Limited | Professional & scientific | 1974 |
| John Monaghan Limited | Wholesale & retail | 2005 |
| Johnsons Facilities Limited | Construction | 2023 |
| Johnsons Property Services Group Holdings Ltd | Financial services | 2023 |
| Jorden Heath Limited | Wholesale & retail | 2021 |
| Joss Arnott Productions Limited | Education | 2024 |
| Jovad Limited | Real estate | 2026 |
| Jowett Motor Manufacturing Company Limited | Manufacturing | 2019 |
| JP Construction (Yorkshire) Ltd | Construction | 2023 |
| JP Marketplace Limited | Wholesale & retail | 2025 |
| JPF Solutions Limited | Energy | 2013 |
| JS Recruitment UK Ltd | Administrative & support | 2013 |
| JSA Home Improvements Ltd | Construction | 2015 |
| JSB Hublock Limited | Manufacturing | 2006 |
| Jsil Consultancy Limited | Professional & scientific | 2020 |
| Jucy Estates Ltd | Hospitality | 2022 |
| Just Leasing Limited | Administrative & support | 2020 |
| Justgardendining Ltd | Wholesale & retail | 2025 |
| Justgardensofas Limited | Wholesale & retail | 2025 |
| Justparasols Limited | Wholesale & retail | 2019 |
| K Charles & SON Limited | Construction | 2010 |
| K Displays Limited | Manufacturing | 2020 |
| K Pharm Ltd | Health & social care | 2025 |
| K&G Commercials Ltd | Wholesale & retail | 2024 |
| K.Smith Electrical Ltd | Construction | 2021 |
| KA Cars (Yorkshire) Ltd | Wholesale & retail | 2018 |
| Kahoy Ltd | Manufacturing | 2017 |
| Karl Cole Commercial Solutions Limited | Administrative & support | 2013 |
| Karmend (Ossett) Limited | | 1966 |
| Kdan Ltd | Administrative & support | 2019 |
| KDH Safety Netting Services Ltd | Construction | 2025 |
| Kelvin Burke Limited | Professional & scientific | 2016 |
| KEN Clarke Limited | Wholesale & retail | 1974 |
| Kensington Beauty Ltd | Other services | 2019 |
| Kent Interiors Ltd | Wholesale & retail | 2025 |
| Kenworthy Coaching Ltd | Professional & scientific | 2025 |
| Kera Properties Ltd | Real estate | 2023 |
| KEV Spurr Scrap & Waste Services Ltd | Water & waste | 2025 |
| Key 2 Outstanding Limited | Health & social care | 2017 |
| Key Fire and Security Limited | Administrative & support | 2013 |
| Key Security (Central) Limited | Administrative & support | 2021 |
| Key Security (Midlands) Limited | Administrative & support | 2021 |
| Key Security (UK) Ltd | Administrative & support | 2007 |
| Key Security Group Limited | Administrative & support | 2015 |
| Kidz Aware Limited | Information & communication | 2006 |
| Killgerm Chemicals Limited | Manufacturing | 1993 |
| Killgerm Group Limited | Professional & scientific | 1976 |
| Kings Yard Property Company Limited | Real estate | 2025 |
| Kingsman Security Ltd | Administrative & support | 2021 |
| Kingston Connect Ltd | Information & communication | 2025 |
| Kingsway Grove Management Company Limited | Real estate | 2021 |
| Kinsley Car Sales Ltd | Wholesale & retail | 2026 |
| Kinway Hand Car Wash Ltd | Wholesale & retail | 2021 |
| KIP Mcgrath Ossett LLP | | 2024 |
| Kirkheaton Popular Music Choir | Arts & recreation | 2022 |
| Kirsty Wright Ltd | Professional & scientific | 2023 |
| Kitchens by Design (Yorkshire) Limited | Other services | 2009 |
| Kixx Wakefield West Yorkshire Ltd | Education | 2020 |
| KLH Properties Ltd | Real estate | 2023 |
| KLJ Commercials Ltd | Wholesale & retail | 2022 |
| KN Painting and Decorating Ltd | Construction | 2024 |
| Koko Hair Ossett Limited | Other services | 2024 |
| Kolorcraft Group Limited | Manufacturing | 1998 |
| Kolorcraft Holdings Limited | Financial services | 2019 |
| Kolorcraft Limited | Manufacturing | 1979 |
| Kovatech Ltd | Wholesale & retail | 2026 |
| KP Goods Ltd | Wholesale & retail | 2021 |
| Kreativ Installations Limited | Construction | 2025 |
| Kroe Investments Ltd | Wholesale & retail | 2023 |
| L.A. Brook Limited | Wholesale & retail | 1959 |
| Lakeside Hilton Limited | Professional & scientific | 2010 |
| Lark Logistics Ltd | Transport & logistics | 2021 |
| LB Leeds Catering Ltd | Hospitality | 2020 |
| Leapwvfaith Ltd | Wholesale & retail | 2019 |
| Leeds Coffee Emporium Ltd | Hospitality | 2023 |
| Leeds Motorcycle Training Ltd | Education | 2019 |
| Leeds School of Motorcycling Ltd | Education | 2019 |
| Leodis IT Services Ltd | Information & communication | 2024 |
| Lews Fitness Ltd | Arts & recreation | 2025 |