| K T Construction (Elmer) Limited | Construction | 2003 |
| K&S Consultancy Sussex Ltd | Health & social care | 2011 |
| K.D.P. Software Limited | Information & communication | 1987 |
| K.L.J. Business Management Limited | Professional & scientific | 1987 |
| K9 Deployment Limited | Administrative & support | 2010 |
| Kaaservices Limited | Education | 2015 |
| KAD Properties Limited | Construction | 2014 |
| KAH Training Solutions Limited | Information & communication | 2013 |
| KAI Health Limited | Health & social care | 2012 |
| Kakakatyandjames Ltd | Households | 2018 |
| Kamluya Electrical Ltd | Wholesale & retail | 2026 |
| Kamruddin Consulting Ltd | Information & communication | 2019 |
| Kapstone Limited | Professional & scientific | 2013 |
| Karen Hampton Ltd | Administrative & support | 2016 |
| Karl Merridue Carpentry Limited | Construction | 2015 |
| Karrma Digital Ltd | Professional & scientific | 2025 |
| Karrot Developments Limited | Manufacturing | 2013 |
| Katchadan Self Storage Limited | Other services | 2020 |
| Katie Fine Arts Ltd | Construction | 2022 |
| Katurn Mortgages Ltd | Financial services | 2018 |
| Kaybus Limited | Real estate | 2003 |
| Kaysted Limited | Wholesale & retail | 2011 |
| KB Appliance Repair Limited | Administrative & support | 2024 |
| KB Machine Learning Ltd | Information & communication | 2023 |
| KC2 Properties Limited | Real estate | 2021 |
| KC2 Solutions Limited | Transport & logistics | 2015 |
| KCD Lighting Limited | Information & communication | 2023 |
| KCK Properties Limited | Construction | 2002 |
| Keane Boiler Services Ltd | Construction | 2013 |
| Keane Goose Ltd | Information & communication | 2021 |
| Kebab Carvery Limited | Hospitality | 2024 |
| Keebee Developments (Woodlands) Ltd. | Real estate | 1996 |
| Keebee Developments Limited | Construction | 1995 |
| Keebee Hampshire Limited | Construction | 2000 |
| Keebee Marine Developments Ltd | Construction | 2012 |
| Keel Clear Ltd | Manufacturing | 2026 |
| Keelings Retail Ltd | Wholesale & retail | 2021 |
| Keith Chandler Limited | Professional & scientific | 2005 |
| KEL Developments 1 Limited | Construction | 2023 |
| KEL Developments 2 Limited | Construction | 2023 |
| Kelbicom Limited | Information & communication | 2011 |
| Kelburn Property Clearance Ltd | Water & waste | 2025 |
| Kelcher Construction Ltd | Construction | 2025 |
| Keller Monroe Limited | Administrative & support | 2014 |
| Kenny Relf Surveyors Ltd | Professional & scientific | 2024 |
| Kenny Solicitors Limited | Professional & scientific | 2009 |
| Kensington Reed Ltd | Construction | 2026 |
| Kenton Budd Ltd | Real estate | 2015 |
| Kerners Investment Company | Other services | 2017 |
| Kerry Mcmahon Travel Ltd | Administrative & support | 2025 |
| Keshira Creative Limited | Hospitality | 2022 |
| Kesley Investments Limited | Real estate | 1999 |
| Ketting Limited | Professional & scientific | 2006 |
| Kevinox Stainless Limited | Wholesale & retail | 2016 |
| Kewbzuk Ltd | Wholesale & retail | 2022 |
| Key Clinical Solutions Limited | Wholesale & retail | 2024 |
| Key Homes and Construction Ltd | Construction | 2025 |
| Key Nominal Ltd | Information & communication | 2017 |
| Keynor Farm Limited | Other services | 2012 |
| Keynor Properties Limited | Hospitality | 2004 |
| Keynor Salads Limited | Extraterritorial | 1983 |
| KFT Holdings Limited | Real estate | 2016 |
| KGS Properties Ltd | Households | 2023 |
| KH Accountants (Sussex) Ltd | Professional & scientific | 2018 |
| KH Crawley Limited | Wholesale & retail | 2026 |
| KH Fuel Maintenance Ltd | Professional & scientific | 2026 |
| Khadi Papers Limited | Wholesale & retail | 2002 |
| Khameleon Window Cleaning (DR) Limited | Administrative & support | 2011 |
| Khebra Productions Ltd | Arts & recreation | 2021 |
| Kiddy Klobber Limited | Wholesale & retail | 2006 |
| Kids Coaching Hive (Schools) Ltd | Education | 2018 |
| Kids Coaching Hive Ltd | Other services | 2018 |
| Kids in Care... HOW CAN I Help? Limited | Professional & scientific | 2022 |
| Kids' ALL Star Sports Ltd | Arts & recreation | 2021 |
| Kieran Munt Carpentry Limited | Construction | 2012 |
| Kildare Limited | Professional & scientific | 1979 |
| KIM Prichard Consultancy Limited | Health & social care | 2015 |
| Kimbridge House Ltd | Households | 2005 |
| KIN Connect Ltd | Professional & scientific | 2020 |
| Kinbrook Ltd | Real estate | 2019 |
| King & Drury Construction Ltd | Construction | 2013 |
| Kingfisher & Maxwell Ltd | Hospitality | 2023 |
| Kingfisher Creative Architectural Design Limited | Professional & scientific | 2013 |
| Kingley Vale Lime and Flint Ltd | Extraterritorial | 2021 |
| Kingmere Limited | Real estate | 1997 |
| Kings Bloodstock (Sussex) Limited | Agriculture & fishing | 2016 |
| Kingsbridge Estates Limited | Construction | 2001 |
| Kingscroft Management Limited | Administrative & support | 1986 |
| Kingsey Properties Limited | Administrative & support | 2006 |
| Kinibito Limited | Information & communication | 2019 |
| Kinocad Services Limited | Manufacturing | 2018 |
| Kinra Advisory Limited | Professional & scientific | 2026 |
| Kinstore Limited | Other services | 2004 |
| Kirk & Lyons Limited | Professional & scientific | 2024 |
| Kirsop-Taylor Healthcare Ltd | Health & social care | 2008 |
| Kitch Media Ltd | Professional & scientific | 2013 |
| Kite Barns Management Limited | Real estate | 2024 |
| Kittiwake Homes Ltd | Real estate | 2021 |
| Kiwi Media and Promotions Ltd | Arts & recreation | 2015 |
| KJ FOX Ltd | Real estate | 2015 |