| Kate Haynes Limited | Professional & scientific | 2003 |
| Katec Post Ltd | Wholesale & retail | 2018 |
| Katemba Limited | Information & communication | 2000 |
| Kathglade Holdings Limited | Professional & scientific | 1997 |
| Kayak & Company Limited | | 1980 |
| Kays Caring Angels Ltd | Health & social care | 2023 |
| KAZ Sports and Leisure Limited | Manufacturing | 2005 |
| KB Solutions Limited | Information & communication | 1987 |
| KB Tester Ltd | Other services | 2017 |
| KC Environmental Limited | Professional & scientific | 2006 |
| KC Rentals & Properties Ltd | Real estate | 2025 |
| Kccache Global Recruitment Limited | Transport & logistics | 2024 |
| KCH Electrical Limited | Construction | 2017 |
| KCH MOT Centre Ltd | Wholesale & retail | 2016 |
| Kd&Daughters Ltd | Real estate | 2019 |
| KDF Limited | Information & communication | 2016 |
| Kea-Flex Mouldings Limited | Manufacturing | 1958 |
| Kearton Close Ltd | Construction | 2021 |
| Keegan Consultancy Ltd | Administrative & support | 2017 |
| Keep Active Muscles Ltd | Arts & recreation | 2022 |
| Keith Saunders Limited | Administrative & support | 2002 |
| Keith Woodhouse Ltd | Information & communication | 2005 |
| Kell & Associates Limited | Professional & scientific | 2003 |
| Kelly Distribution Limited | | 1999 |
| Kelsey House Bar & Kitchen Ltd | Hospitality | 2006 |
| Kelvin Lyons Consultancy Limited | Construction | 2006 |
| Kenley Business Solutions Limited | Professional & scientific | 2003 |
| Kensa Business Solutions Limited | Administrative & support | 2003 |
| Kensington Autocare Limited | Administrative & support | 1997 |
| Kensington Designs Limited | Construction | 1999 |
| Kent Retreads Limited | Transport & logistics | 1990 |
| Kerrico Limited | Administrative & support | 2003 |
| Kerry's Hair Design Ltd | Other services | 2003 |
| Kevin Jordan Limited | Other services | 1995 |
| KEW Road (2527) Limited | | 2009 |
| Key Flats Limited | Construction | 1994 |
| Keymex Limited | Wholesale & retail | 1994 |
| Keyshift (People) Ltd | Professional & scientific | 1996 |
| Keyword Computer Services Limited | Professional & scientific | 1996 |
| KH Hometech Services Ltd. | Information & communication | 2021 |
| KHM Realty Ltd. | Real estate | 2024 |
| KHS London Ltd | Wholesale & retail | 2021 |
| Khushbu Ltd | Other services | 2025 |
| Khushi Takeaway Ltd | Hospitality | 2016 |
| Kids-Biz Limited | Wholesale & retail | 2004 |
| Kidztalk Limited | Information & communication | 2002 |
| Kieranna Limited | Real estate | 2017 |
| Kightsbridge Consultancy Ltd | Professional & scientific | 1995 |
| Kilcavan Limited | Construction | 1999 |
| Kilindini Shipping Limited | Transport & logistics | 2005 |
| Kilnmark Limited | Professional & scientific | 2019 |
| Kimberley Motors Limited | | 1982 |
| Kimpton Court Management Company Limited | Households | 2005 |
| Kind Canyon Digital Limited | Arts & recreation | 2005 |
| Kinetrol Limited | Manufacturing | 1958 |
| King Charles Road Management Limited | Professional & scientific | 2006 |
| King Consultants Ltd | Professional & scientific | 2001 |
| King's House School Trust (Richmond) Limited | Education | 1957 |
| Kingenious Limited | Wholesale & retail | 2023 |
| Kingfisher Seafoods Limited | Wholesale & retail | 2004 |
| Kingfix Limited | Manufacturing | 2004 |
| Kings Accounting House Limited | Professional & scientific | 2005 |
| Kingsbridge Park (Oxted) Management Company Limited | Households | 2000 |
| Kingscroft Insurance Company Limited | Financial services | 1976 |
| Kingsdown School, Skills and Enterprise Limited | Education | 2006 |
| Kingsland Suppliers Limited | | 1981 |
| Kingsley Haulage Limited | Professional & scientific | 2002 |
| Kingsmead Management Limited | Households | 1988 |
| Kingston Liberal Democrat Property Co. Limited | Real estate | 2002 |
| Kingston Mitra Mandal CIC | Other services | 2023 |
| Kingston Property Development Limited | Real estate | 2004 |
| Kingston-Upon-Thames Specsavers Limited | Wholesale & retail | 1993 |
| Kingston-Upon-Thames Visionplus Limited | Wholesale & retail | 1993 |
| Kingsway Building Contractors (Kenton) Limited | Construction | 1951 |
| Kingswood Property & Developments Limited | Real estate | 1986 |
| Kingswood UK Home Ltd | Hospitality | 2010 |
| Kirupa Ltd | Real estate | 2022 |
| Kithigh Limited | | 1985 |
| KJ Development Limited | Professional & scientific | 2007 |
| KJC17 Limited | Health & social care | 2019 |
| KK & Sons Private Limited | Wholesale & retail | 2020 |
| Kkss Ltd | Information & communication | 2008 |
| Klarem Limited | Professional & scientific | 1999 |
| Klicksi Limited | Wholesale & retail | 1983 |
| KMS Properties Ltd | Real estate | 2014 |
| KMS Services Limited | Administrative & support | 2004 |
| Knew Beginning Limited | Administrative & support | 2006 |
| Knewco Limited | Financial services | 1992 |
| Knighton Motors Limited | Wholesale & retail | 2001 |
| Knights Park Estates Limited | Other services | 1993 |
| KNK Building Services Limited | Construction | 1997 |
| Knowledge & Analytical Foundation Limited | Information & communication | 2012 |
| Knowledge Valley Ltd | Professional & scientific | 2023 |
| Knowledgebridge AI Limited | Administrative & support | 2025 |
| Kogame & Co. Limited | Professional & scientific | 2005 |
| Kojo & Company Limited | Professional & scientific | 2002 |
| Kojo Consultancy Services Limited | Financial services | 1999 |
| Kokulam Limited | Real estate | 2020 |
| Koleejan Limited | Information & communication | 2005 |
| Komfort Developments Limited | Real estate | 2002 |