| Lara Style Closet Ltd | Professional & scientific | 2023 |
| Lark Rise Management Company Limited | Households | 2006 |
| Laser Byte Limited | Information & communication | 1983 |
| Latentics Ltd | Information & communication | 2026 |
| Laterite Pictures Limited | Information & communication | 2023 |
| Latitudes Limited | Real estate | 2005 |
| Lattitude Consultancy Limited | Professional & scientific | 2003 |
| Launch Learning Ltd | Education | 2026 |
| Lauren Joyce Ltd | Health & social care | 2025 |
| LAV Engineering Limited | Professional & scientific | 2017 |
| Lavender Motors Holdings Limited | Financial services | 2019 |
| Lavender Motors Limited | Wholesale & retail | 1988 |
| Lavender Property Services Limited | Construction | 2012 |
| Lavington Caring CIC | Hospitality | 2025 |
| Lawdog Media Law Limited | Professional & scientific | 2019 |
| Lawhill Worldwide Limited | Manufacturing | 2013 |
| Lawn Events Limited | Hospitality | 2010 |
| Lazige Ltd | Professional & scientific | 2026 |
| LB Aerotech Ltd | Manufacturing | 2021 |
| LBE Landscaping Limited | Construction | 2010 |
| LD Event Equipment Hire Ltd | Arts & recreation | 2025 |
| Lea-White Property Co Limited | Real estate | 2018 |
| Lea-White Signature Builds Ltd | Construction | 2025 |
| Lead Paint Survey Limited | Wholesale & retail | 2016 |
| Lead Survey Ltd | Professional & scientific | 2016 |
| Leaders Improve Limited | Professional & scientific | 2018 |
| Leadership Immersions Ltd | Education | 2023 |
| Leading With Nature Limited | Professional & scientific | 2015 |
| Leadra Ltd | Professional & scientific | 2016 |
| Leafs & Beans Limited | Real estate | 2024 |
| Leaping Tortoise Ltd | Real estate | 2020 |
| Learnhuman Ltd | Information & communication | 2021 |
| Learning Ventures Limited | Education | 2010 |
| Ledger and Vine Ltd | Wholesale & retail | 2025 |
| Ledgerz Ltd | Information & communication | 2021 |
| Leekewmoss Ltd | Arts & recreation | 2019 |
| Leeor Levy Consulting Limited | Professional & scientific | 2015 |
| Leeway Farm Services Ltd | Agriculture & fishing | 2020 |
| Leeway Services Ltd | Manufacturing | 2015 |
| Leeway Woodwork Ltd | Manufacturing | 2022 |
| Legendsandoutlawsevents Ltd | Administrative & support | 2025 |
| Leigh Gilbert Ltd | Professional & scientific | 2021 |
| Leigh Watermill Ltd | Professional & scientific | 2023 |
| Lemon Assets LLP | | 2018 |
| Lenand Limited | Financial services | 2022 |
| Lenmark Construction Limited | Construction | 2011 |
| Lenmark Holdings Limited | Professional & scientific | 2015 |
| LEO Power Ltd | Administrative & support | 2017 |
| Leone Developments Limited | Construction | 2019 |
| Leone Holdings Limited | Real estate | 2021 |
| Leone Homes Limited | Construction | 2020 |
| Leone Properties Limited | Real estate | 2010 |
| Leone Seafront Limited | Real estate | 2025 |
| Less IS Progress Limited | Information & communication | 2021 |
| LET ME Explane Ltd | Administrative & support | 2014 |
| Let's Cook Private Chef Ltd | Hospitality | 2022 |
| Lewry Developments Limited | Construction | 2013 |
| Lexicon School Ltd | Education | 2018 |
| LG Solutions Ltd | Administrative & support | 2024 |
| Liaison Systems Limited | Administrative & support | 2007 |
| Liberty Land and Buildings Ltd | Construction | 2022 |
| Liberty Talent Ltd | Administrative & support | 2024 |
| Liddle Consultancy Services Limited | Professional & scientific | 2024 |
| Life's Great Adventure Ltd | Information & communication | 2006 |
| Lift & Shift Factory & Plant Limited | Water & waste | 2005 |
| Lighthaus Design Ltd | Professional & scientific | 2014 |
| Lighthouse Instruments Europe Limited | Wholesale & retail | 2017 |
| Lighthouse Mercury Limited | Wholesale & retail | 2004 |
| Ligo Logistics Limited | Transport & logistics | 2024 |
| Lilac Palm Limited | Arts & recreation | 2005 |
| Lily & Fluff Ltd | Information & communication | 2020 |
| Lime Tree Designs & Planning Ltd. | Professional & scientific | 2013 |
| Limepalm Limited | Arts & recreation | 2009 |
| Limes Restaurant Ltd. | Hospitality | 2012 |
| Lincoln Binns Limited | Manufacturing | 1985 |
| Lindfield Bonfire Society Limited | Arts & recreation | 1999 |
| Lindfield Carpentry Ltd | Construction | 2024 |
| Lindfield Commodities Ltd | Professional & scientific | 2022 |
| Lindfield Eyecare Limited | Agriculture & fishing | 2013 |
| Lindfield Juniors FC Limited | Arts & recreation | 2026 |
| Lindfield Repair Cafe C.I.C. | Other services | 2021 |
| Linear Health & Fitness Limited | Arts & recreation | 2014 |
| Link (DMS) Ltd | Administrative & support | 2003 |
| Links Construction Limited | Construction | 2025 |
| Lion of Judah Band Ltd | Manufacturing | 2020 |
| Lisa Bradburn Design Ltd | Other services | 2014 |
| Listing Solutions Ltd | Professional & scientific | 2026 |
| Litewarp Ltd | Construction | 2023 |
| Little Acorn Holdings Limited | Real estate | 2019 |
| Little Bentswood Limited | Construction | 2011 |
| Little Broomsticks Ltd | Hospitality | 2025 |
| Little Cygnets Ltd | Health & social care | 2026 |
| Little Hair Boutique (Sussex) Ltd | Other services | 2025 |
| Little John Engineering Ltd | Information & communication | 2019 |
| Little Orchard Services Limited | Hospitality | 2022 |
| Little Tinkers Baby and Child First AID Ltd | Health & social care | 2024 |
| Littlecote House (Lindfield) Management Company Limited | Households | 2005 |
| Live Avinit Technical Limited | Information & communication | 2022 |
| Live in London Ltd | Real estate | 2016 |
| Living Danish Ltd | Construction | 2018 |