| Kitchen Carousel Ltd | Manufacturing | 2017 |
| Kittyhawk Flight Academy Limited | Education | 2022 |
| Kittyhawk UN Limited | Arts & recreation | 2020 |
| KJ Executors Limited | Professional & scientific | 2024 |
| KJB Electrical Limited | Construction | 2009 |
| KJM Communications Limited | Information & communication | 2023 |
| Klays Kool Ltd | Manufacturing | 2025 |
| KMP Homes Ltd | Construction | 2025 |
| Knapthorpe Ltd | Professional & scientific | 2022 |
| Knight Chapman Psychological Limited | Professional & scientific | 1988 |
| Knill James LLP | | 2019 |
| Knot Just Carpentry and Joinery Ltd | Construction | 2021 |
| Kroto Film & Design Ltd | Information & communication | 2008 |
| Krsna Property Ltd | Real estate | 2026 |
| KSM Property Holdings Limited | Real estate | 2020 |
| KW Motors Sussex Ltd | Wholesale & retail | 2024 |
| Kwantic Limited | Information & communication | 2023 |
| Kyndra Ltd | Wholesale & retail | 2024 |
| L J W Plumbing & Heating Ltd | Construction | 2021 |
| L T Pickering Architects Limited | Professional & scientific | 2012 |
| L&F Publishing Ltd | Arts & recreation | 2020 |
| L&M Bespoke Ltd | Construction | 2026 |
| Lab-Serv Limited | Professional & scientific | 2021 |
| LAB8 Recruitment Limited | Administrative & support | 2023 |
| Ladd VFX Limited | Information & communication | 2023 |
| Lady M Occasion Wear Ltd | Wholesale & retail | 2022 |
| Lagom Design Limited | Manufacturing | 2007 |
| Lagoon Property Limited | Real estate | 2015 |
| Lake Street Holdings Limited | Real estate | 2025 |
| Lakecrest Properties Limited | Real estate | 1997 |
| Landed Creative Ltd | Professional & scientific | 2022 |
| Landport Foodstores Limited | Wholesale & retail | 2022 |
| Landport Sales and Marketing Limited | Administrative & support | 2022 |
| Landport Youth Centre | Arts & recreation | 2012 |
| Landworks LLC | | 2023 |
| Langridge Limited | Professional & scientific | 2010 |
| Langtons Hairdressing Limited | Other services | 2003 |
| Lanternsoft Limited | Information & communication | 2009 |
| Larch Health & Safety Limited | Professional & scientific | 2024 |
| Larchwood Fraser Limited | Professional & scientific | 2014 |
| Larringford Holdings Limited | Real estate | 2026 |
| Laser on Tour Brighton Ltd | Other services | 2025 |
| Lasting Transformation Ltd | Professional & scientific | 2011 |
| Lastover Limited | Professional & scientific | 2020 |
| Laughton Lodge Management and Services Company Limited | Energy | 2012 |
| Launchbury Aviation and Marine Limited | Professional & scientific | 2013 |
| Laura Oates Ltd | Professional & scientific | 2023 |
| Laurence Turrell & Co Ltd | Administrative & support | 2017 |
| Law Easier Limited | Administrative & support | 2017 |
| Lawrence & Taylor LP | | 2022 |
| Lazywisdom Ltd | Education | 2018 |
| Leading With Compassion Ltd | Extraterritorial | 2025 |
| League of the Helping Hand(The) | Health & social care | 1935 |
| Leams END Advisory Limited | Professional & scientific | 2021 |
| Leanne Rebekah Hair Ltd | Other services | 2024 |
| Learn My Way Ltd | Education | 2025 |
| Leaselogic Limited | Professional & scientific | 1991 |
| Lees Estates Limited | Real estate | 2019 |
| Leni Miller Associates Limited | Construction | 1993 |
| Leoframes Limited | Wholesale & retail | 2017 |
| Lets Talk Project Community CIC | Other services | 2026 |
| Lewes 2000 F.C. Ltd | Arts & recreation | 1999 |
| Lewes Bonfire Game CIC | Manufacturing | 2024 |
| Lewes Chiropractic Clinic Limited | Health & social care | 2003 |
| Lewes Climate Hub Community Interest Company | Professional & scientific | 2021 |
| Lewes Community Screen | Information & communication | 2012 |
| Lewes Community Screen (Trading) Limited | Hospitality | 2017 |
| Lewes County Cars Limited | Transport & logistics | 2024 |
| Lewes Cuts Barber Ltd | Other services | 2025 |
| Lewes Design Contracts Limited | Construction | 1966 |
| Lewes District Taxis Ltd | Transport & logistics | 2024 |
| Lewes FC Women Limited | Arts & recreation | 2018 |
| Lewes Financial Consulting Limited | Professional & scientific | 2023 |
| Lewes Football Club Holdings Ltd | Arts & recreation | 2025 |
| Lewes Football Foundation Ltd | Arts & recreation | 2024 |
| Lewes Glass Ltd. | Other services | 2011 |
| Lewes Golf Club Limited | Arts & recreation | 1979 |
| Lewes Golf Club Trading Limited | Arts & recreation | 2019 |
| Lewes Health Food Shop Ltd | Wholesale & retail | 2022 |
| Lewes Home Improvements Limited | Construction | 2018 |
| Lewes Housing Investment Company Limited | Construction | 2017 |
| Lewes Local C.I.C. | Administrative & support | 2010 |
| Lewes Ltd | Hospitality | 2025 |
| Lewes Money MAN Ltd | Professional & scientific | 2022 |
| Lewes Music Festival Limited | Arts & recreation | 2023 |
| Lewes Old Grammar School Trust | Education | 2015 |
| Lewes Old Racecourse Management Company Limited | Real estate | 1985 |
| Lewes Pilot GIG Club | Arts & recreation | 2025 |
| Lewes Priory Cricket Club Limited | Arts & recreation | 2025 |
| Lewes Priory Trust | Administrative & support | 2008 |
| Lewes Ripple Community Interest Company | Arts & recreation | 2019 |
| Lewes Rowing Club | Other services | 2025 |
| Lewes Rugby Football Club Limited | Arts & recreation | 2004 |
| Lewes Smugglers Limited | Other services | 2022 |
| Lewes Sports Club Limited | Arts & recreation | 2024 |
| Lewes Taxis Ltd | Transport & logistics | 2021 |
| Lewes Town of Culture Partnership CIC | Education | 2026 |
| Lewes Turkish Barbers Ltd | Other services | 2021 |
| Lewes Yellow Taxis Ltd | Transport & logistics | 2024 |
| Leweslight Community Interest Company | Education | 2017 |