| Justera Limited | Wholesale & retail | 2024 |
| Justice Law & Legal Advice Centre Ltd | Professional & scientific | 2025 |
| JV Civils Limited | Construction | 2019 |
| JVS HR Consulting Limited | Administrative & support | 2018 |
| JVW Ltd | Transport & logistics | 2024 |
| JWA Trading Limited | Wholesale & retail | 2018 |
| K & a World Ltd | Wholesale & retail | 2020 |
| K & M Fires Ltd | Construction | 2021 |
| K a Waite Limited | Construction | 2004 |
| K C S Group Limited | Arts & recreation | 2000 |
| K J Allen Transport Ltd | Transport & logistics | 2015 |
| K P Glass Ltd | Wholesale & retail | 2002 |
| K R Litchfield Limited | Administrative & support | 2006 |
| K R Properties Investment Limited | Real estate | 2016 |
| K Vanterpool Consultancy Limited | Professional & scientific | 2015 |
| K Wright Consultancy Limited | Professional & scientific | 2021 |
| K&F Enterprises Ltd | Hospitality | 2024 |
| K&F Properties Development Ltd | Real estate | 2025 |
| K&I Consultancy Services Ltd | Information & communication | 2025 |
| K&T Store Ltd | Wholesale & retail | 2025 |
| K. S Walsh Plumbing & Heating Ltd | Construction | 2022 |
| K.C Building and Masonry Ltd | Construction | 2026 |
| K.C.U. Ltd. | Health & social care | 2006 |
| K.D.T. Plastering Limited | Construction | 2005 |
| K.J Construction UK Limited | Construction | 2009 |
| K.M Beauty Aesthetician Ltd | Other services | 2023 |
| K.R. Properties (Kettering) Limited | Construction | 1980 |
| K1 Nails and Spa Ltd | Other services | 2026 |
| K3 Moves Ltd | Wholesale & retail | 2019 |
| Kabeer & Co Ltd | Other services | 2017 |
| Kadoshpvt Ltd | Administrative & support | 2025 |
| Kadovyah Ltd | Manufacturing | 2025 |
| Kady Accounting Ltd | Professional & scientific | 2012 |
| Kady JH Ltd | Transport & logistics | 2015 |
| Kaha Holdings Limited | Financial services | 2025 |
| Kain Enterprises Ltd | Real estate | 2025 |
| Kajdan Transport Ltd | Transport & logistics | 2017 |
| Kala Supermarket Ltd | Wholesale & retail | 2020 |
| Kalinac Property Repairs Ltd | Construction | 2025 |
| Kalon Industries Limited | Professional & scientific | 2025 |
| Kamela Transport Ltd | Transport & logistics | 2020 |
| Kameo SA Ltd | Real estate | 2023 |
| Kamil Lason Transport Ltd | Transport & logistics | 2015 |
| Kandfgroupservices Ltd | Transport & logistics | 2025 |
| Kandje Limited | Professional & scientific | 2023 |
| Kang Properties Investments Limited | Real estate | 2018 |
| Kanolty Distribution Limited | Transport & logistics | 1997 |
| Karadal Properties Limited | Real estate | 2018 |
| Karadal Property Management Ltd | Real estate | 2020 |
| Karen Knightly Property Ltd | Real estate | 2022 |
| Kariona Ltd | Wholesale & retail | 2022 |
| Karldr Installation Ltd | Professional & scientific | 2022 |
| Karlsports Ltd | Wholesale & retail | 2009 |
| Karus Investments Limited | Real estate | 2024 |
| Karus Systems Limited | Information & communication | 1998 |
| Katarina Holdings Ltd | Financial services | 2024 |
| Katzenink Ltd | Other services | 2025 |
| Katzenworld Ltd | Wholesale & retail | 2014 |
| Kaur Aura Ltd | Health & social care | 2021 |
| Kavak Holding Ltd | Financial services | 2019 |
| KAY & CEE LLP | | 2010 |
| KAY Electrical Services Ltd | Construction | 2021 |
| Kaysha Kareway Limited | Health & social care | 2016 |
| Kaziboni Financial Services Ltd | Financial services | 2025 |
| KBR Construction Consultants Limited | Professional & scientific | 2013 |
| KC Performance Ltd | Education | 2026 |
| KCB Property Investors Ltd | Professional & scientific | 2023 |
| KCK Property Services Ltd | Administrative & support | 2023 |
| KCM Property Management Ltd | Real estate | 2019 |
| KCS Properties Limited | Financial services | 2015 |
| KD Terrin Limited | Professional & scientific | 2014 |
| KDP Rentals Ltd | Real estate | 2015 |
| KEE I.T. Services Limited | Administrative & support | 2003 |
| KEE Network Services Limited | Information & communication | 1997 |
| Keelings Fresh International Limited | Wholesale & retail | 2006 |
| Keelings International Limited | Wholesale & retail | 1982 |
| Keista PTY Limited | Transport & logistics | 2025 |
| Keith Fountain Limited | Administrative & support | 2012 |
| Keith Shuttleworth and Associates Limited | Professional & scientific | 1994 |
| Kelvington Ltd | Professional & scientific | 2020 |
| KEN Hall Limited | Manufacturing | 1965 |
| Kennedy Recruitment Consulting Limited | Administrative & support | 2025 |
| Kennedy&Co Property Sourcing Ltd | Real estate | 2026 |
| Kensigns Limited | Manufacturing | 2002 |
| Kensingston Vale Ltd | Information & communication | 2025 |
| Kensington Consulting Group Ltd | Information & communication | 2024 |
| Kestrel GAS Ltd | Construction | 2023 |
| Kett Limited | Extraterritorial | 1997 |
| Kettering Catering Ltd | Hospitality | 2026 |
| Kettering Auto Electrics Ltd | Wholesale & retail | 2020 |
| Kettering Autospray Limited | Administrative & support | 2010 |
| Kettering Bituminous Products Limited | Professional & scientific | 1989 |
| Kettering Car Recycling Ltd | Water & waste | 2019 |
| Kettering Car Wash Ltd | Administrative & support | 2025 |
| Kettering Carpet Supply Ltd | Wholesale & retail | 2019 |
| Kettering Cleaning Club CIC | Administrative & support | 2025 |
| Kettering Community Trust Limited | Arts & recreation | 2006 |
| Kettering Community Woodlands Limited | Agriculture & fishing | 2026 |
| Kettering Computer Solutions Limited | Information & communication | 2016 |
| Kettering Convenience Stores Ltd | Wholesale & retail | 2024 |