| KC Residential Estate Management Company Ltd | Real estate | 2017 |
| KEA Court Residents Limited | Households | 2018 |
| Keep Design & Development Ltd | Professional & scientific | 2013 |
| Keith Hall Construction Limited | Construction | 2019 |
| Kelting Limited | Hospitality | 2000 |
| Kendall Care Limited | Health & social care | 2021 |
| Kenhurst Surveyors Ltd | Professional & scientific | 2022 |
| Kent Mini Market Ltd | Wholesale & retail | 2023 |
| Kent Paintball Limited | Arts & recreation | 2020 |
| Kentcoast Limited | Real estate | 1992 |
| Kessel Holdings Ltd | Financial services | 2026 |
| Kewferry Planning Limited | Extraterritorial | 2020 |
| KFL Advisory Limited | Other services | 2026 |
| KGS Care Haven Ltd | Health & social care | 2025 |
| Kimber Plumbing and Heating Limited | Construction | 2013 |
| Kingdom Designers Ltd | Manufacturing | 2025 |
| Kingdom Products Ltd | Wholesale & retail | 2016 |
| Kingfisher Park (Felbridge) Management Company Limited | Households | 2026 |
| Kings Court Residents Association (Lancing) Limited | Households | 1981 |
| Kings Court Residents Association Limited | Households | 1978 |
| Kingston Arch Ltd | Professional & scientific | 2024 |
| Kingston Gorse Estate (Sussex) Limited | Households | 1932 |
| Kingston Park Estate Limited | Households | 1994 |
| King`S Court Freehold Limited | Households | 2007 |
| Kinohill Limited | Real estate | 1979 |
| Kitlea Estates(Sussex)Limited | Real estate | 1956 |
| Kiwi Spas Ltd | Wholesale & retail | 2014 |
| KJ Security Ltd | Administrative & support | 2023 |
| KJD Composites Ltd | Manufacturing | 2023 |
| KJN Solutions Limited | Construction | 2025 |
| KL Foods Ltd | Hospitality | 2025 |
| Kmgcapitalgroup Ltd | Financial services | 2025 |
| KND Creative UK Limited | Information & communication | 2019 |
| Knights RMC Godstone Residents Management Company Limited | Real estate | 2016 |
| Knightscroft House Limited | Real estate | 2006 |
| Knowledge Sphere Ltd | Administrative & support | 2002 |
| Knucker Studio Ltd | Construction | 2023 |
| KOA Carpentry & Joinery Limited | Construction | 2015 |
| Koalie Property Limited | Real estate | 2020 |
| Kold Studios Ltd | Professional & scientific | 2022 |
| Kore Matter Limited | Real estate | 2006 |
| Koroknai Holdings Ltd | Financial services | 2025 |
| KT Studio Ltd | Professional & scientific | 2021 |
| Kucumba Limited | Professional & scientific | 2007 |
| Kudos Building Ltd | Construction | 2005 |
| Kudos Promotions Limited | Real estate | 2010 |
| Kuhr Engineering Limited | Manufacturing | 1980 |
| Kurditek Ltd | Wholesale & retail | 2026 |
| Kwead Property Developments Ltd | Construction | 2024 |
| Kxhs Advisory Limited | Administrative & support | 2025 |
| Kyno Properties Ltd | Real estate | 2021 |
| L & J Design Ltd | Arts & recreation | 2019 |
| L and J Fire Protection Ltd | Public administration | 2013 |
| L Hampton Kebabs Ltd | Hospitality | 2021 |
| L.G. Electrical Solutions Limited | Construction | 2007 |
| LA Sixty Ltd | Professional & scientific | 2019 |
| Laboratory Vacuum Services Limited | Manufacturing | 2013 |
| Ladybirds Littlehampton Limited | Education | 2012 |
| Land.Sea.Air.Design. Limited | Professional & scientific | 2000 |
| Landmark Services (Sussex) Limited | Administrative & support | 2010 |
| Landwest Limited | Wholesale & retail | 1992 |
| Langmeads Close Management Limited | Households | 2014 |
| Lansdowne Cottages Management Limited | Households | 2013 |
| Larontrol Limited | Manufacturing | 1982 |
| Lash and Thread Ltd | Other services | 2017 |
| Last Call Healthcare Ltd | Administrative & support | 2020 |
| Latham Holdings Limited | Real estate | 2018 |
| Laura's Bookkeeping Services Ltd | Professional & scientific | 2020 |
| Laviks Limited | Information & communication | 2016 |
| LB AMA Limited | Wholesale & retail | 2020 |
| LB Physique Coaching Limited | Other services | 2025 |
| LB Wellness Ltd | Other services | 2021 |
| LC Associates Ltd | Other services | 2009 |
| LC Marine Ltd | Manufacturing | 2020 |
| LDO Property Ltd | Real estate | 2022 |
| LE Roux CAP Limited | Financial services | 2024 |
| Lead Monitors Ltd | Information & communication | 2018 |
| Leap Fundraising Ltd | Professional & scientific | 2019 |
| Lease Car Credit Limited | Administrative & support | 2015 |
| Legend Entertainment Ltd | Information & communication | 2025 |
| Leigh Court Residents Association Limited | Households | 1984 |
| Leisure Vehicles Sussex Ltd | Wholesale & retail | 2020 |
| Lenric C21 Limited | Manufacturing | 2001 |
| Lenric International Ltd | Other services | 1987 |
| Levett & Quinn Limited | Construction | 2020 |
| Levilau Consulting Ltd | Professional & scientific | 2026 |
| Lewis Crathern Kitesurfing Ltd | Arts & recreation | 2021 |
| Lewisoft IT Solutions Limited | Information & communication | 2009 |
| Lexley Homes Ltd | Real estate | 2023 |
| Lifetimecare UK Ltd | Health & social care | 2006 |
| Lilstar Marketing Ltd | Professional & scientific | 2025 |
| Lily's Chocolate Box Ltd | Wholesale & retail | 2023 |
| Lime Green Photography Limited | Professional & scientific | 2003 |
| Lime Wood Place Ltd | Real estate | 2020 |
| Linfield Trading Ltd | Wholesale & retail | 2026 |
| Linton Developments Limited | Extraterritorial | 1958 |
| Linton Sports Ltd | Arts & recreation | 2024 |
| Lion Holdings Limited | Financial services | 2008 |
| Lion MAN Management Limited | Transport & logistics | 2017 |
| Lionvest Trading (UK) Limited | Wholesale & retail | 1997 |