| Kettering Cultural Quarter Limited | Real estate | 2014 |
| Kettering Discount Ltd | Wholesale & retail | 2025 |
| Kettering Doggiez Ltd | Other services | 2021 |
| Kettering Domestic Cleaning Limited | Administrative & support | 2008 |
| Kettering Door Company Limited | Construction | 2014 |
| Kettering Garden Services Ltd | Information & communication | 2023 |
| Kettering Golf Club (1891) Limited | Arts & recreation | 2013 |
| Kettering Hand Car Wash Ltd | Other services | 2025 |
| Kettering Heating & Plumbing Limited | Construction | 2009 |
| Kettering Indian Limited | Hospitality | 2015 |
| Kettering Jennys Ltd | Hospitality | 2023 |
| Kettering Kerala Store Ltd | Wholesale & retail | 2023 |
| Kettering KOI and Ponds Limited | Wholesale & retail | 2002 |
| Kettering Lodge Bowling Club Limited | Arts & recreation | 1983 |
| Kettering Management Company Limited | Administrative & support | 2001 |
| Kettering Market Ltd | Wholesale & retail | 2022 |
| Kettering Motorist Centre Ltd | Wholesale & retail | 2002 |
| Kettering Nails Ltd | Other services | 2024 |
| Kettering Nature Group CIC | Education | 2025 |
| Kettering Pass & Go Ltd | Education | 2026 |
| Kettering Paving Limited | Construction | 2019 |
| Kettering Playsafe Limited | Construction | 2006 |
| Kettering Precision Engineering Limited | Manufacturing | 2014 |
| Kettering Roofing Limited | Construction | 1994 |
| Kettering Roofing Solutions Ltd | Construction | 2023 |
| Kettering School of Boxing Community Interest Company | Arts & recreation | 2019 |
| Kettering Single PLY Roofing Ltd | Construction | 2020 |
| Kettering Storage Solutions Ltd | Transport & logistics | 2012 |
| Kettering Street Art CIC | Arts & recreation | 2024 |
| Kettering Taxi Services Ltd | Transport & logistics | 2021 |
| Kettering Town F. C. Management Ltd. | Arts & recreation | 1988 |
| Kettering Town Harriers | Arts & recreation | 2008 |
| Kettering Transport Limited | Transport & logistics | 2025 |
| Kettering Vehicle Rentals Limited | Wholesale & retail | 2004 |
| Kettering Zizou Limited | Hospitality | 2025 |
| Kettonby Care Limited | Health & social care | 2016 |
| Kettonby Gardens (1-8) Management RTM Company Limited | Households | 2013 |
| KFI Fish and Chips Ltd | Hospitality | 2025 |
| KGG Accountancy and Business Services Ltd | Professional & scientific | 2019 |
| Khadem Logistics Ltd | Transport & logistics | 2018 |
| Khalid Consulting Ltd | Professional & scientific | 2020 |
| KHC Holdings Limited | Professional & scientific | 2019 |
| KHC Signs & Graphics Limited | Manufacturing | 2017 |
| KHC Specialist Centre Limited | Manufacturing | 2019 |
| KHL Ltd | Real estate | 2023 |
| KI Beauty Services Ltd | Transport & logistics | 2024 |
| Kickstop Security Products Ltd | Manufacturing | 1991 |
| Kierten Kooner Mortgages Ltd | Financial services | 2024 |
| Kilgore Films Ltd | Information & communication | 2019 |
| Kimberley Nash Ltd | Health & social care | 2023 |
| Kinder Home Care Services Ltd | Health & social care | 2014 |
| Kindred Education (Cambridgeshire) Limited | Education | 2002 |
| Kindred Education (Cator Park) Limited | Education | 2005 |
| Kindred Education (Essex) Limited | Education | 2004 |
| Kindred Education (Kent) Limited | Education | 1952 |
| Kindred Education (Teddington) LLP | | 2011 |
| Kinetics Communications Limited | Professional & scientific | 1999 |
| Kinetics Create Limited | Professional & scientific | 1995 |
| Kinetics Space Limited | Professional & scientific | 2020 |
| King Family Ltd | Professional & scientific | 2019 |
| King Plumbing & Heating Ltd | Construction | 2024 |
| Kingfisher Commercial Services Limited | Professional & scientific | 2016 |
| Kingfisher Playground Inspections Limited | Construction | 2018 |
| Kingsbrook Associates Limited | Professional & scientific | 2017 |
| Kingsley Learning Foundation | Education | 2011 |
| Kingsley Shipping Solutions Ltd | Transport & logistics | 2024 |
| Kingsley Wayne Garments Ltd | Wholesale & retail | 2019 |
| Kiosik Services Ltd | Transport & logistics | 2015 |
| Kipton Marketing Ltd | Professional & scientific | 2025 |
| Kisstruck Ltd | Administrative & support | 2013 |
| Kitchen Concepts (Kettering) Ltd | Construction | 2018 |
| Kitsiyatota Limited | Construction | 2015 |
| Kitteon Group Holdings Ltd | Financial services | 2022 |
| KJ Dack Ltd | Construction | 2021 |
| KJ Loading Bays Limited | Manufacturing | 2019 |
| Kjlc Holdings Ltd | Financial services | 2024 |
| KK Legacy Ltd | Information & communication | 2026 |
| KKD Farms Ltd | Agriculture & fishing | 2022 |
| KKD Services Groundworks Ltd | Construction | 2018 |
| KKD Transports Ltd | Transport & logistics | 2025 |
| Klatch Collective Ltd | Wholesale & retail | 2022 |
| KLM Taxis Limited | Transport & logistics | 2004 |
| Kloan CRE8IVE Limited | Professional & scientific | 2026 |
| KM Storage Holdings Ltd | Financial services | 2025 |
| KMB Hrizon Ltd | Professional & scientific | 2025 |
| KMC Dwellings Ltd | Real estate | 2018 |
| KMC Holdings Limited | Financial services | 2016 |
| KMM Supplies Ltd | Wholesale & retail | 2018 |
| KMR Group Ltd | Administrative & support | 2018 |
| KMT Products Ltd | Wholesale & retail | 2015 |
| Knight Shift Services Ltd | Administrative & support | 2021 |
| Knightly Property Management Ltd | Real estate | 2023 |
| Knights Bespoke Furniture Limited | Manufacturing | 2021 |
| Knights Property & Electrical Services Limited | Construction | 2025 |
| Know Foot Know Horse Limited | Education | 2008 |
| Know I.T. Consulting Ltd | Information & communication | 2004 |
| KNP Limited | Extraterritorial | 2020 |
| KNP Logistics Limited | Extraterritorial | 2020 |
| KO Homes Ltd | Real estate | 2021 |
| Koda Foods Limited | Manufacturing | 2024 |