| KDV Accountancy Services Ltd | Professional & scientific | 2025 |
| Kelan Solutions Limited | Information & communication | 2009 |
| Kelleher Carpentry Limited | Construction | 2011 |
| Kellen Couriers Ltd | Transport & logistics | 2024 |
| Kelvedon Management Company Limited | Households | 2009 |
| Kenbro Discount Carpet Warehouses Limited | Wholesale & retail | 1976 |
| Kenmary Ltd | Construction | 2015 |
| Kenny & Co Limited | Real estate | 2011 |
| Kenway Southend Management Limited | Households | 2006 |
| Kessou's Estate Limited | Construction | 2022 |
| Kevanden Ltd | Wholesale & retail | 2019 |
| Kextor Trading Limited | Wholesale & retail | 2016 |
| Keychase Limited | Health & social care | 2005 |
| Keyinspect Inventories Limited | Administrative & support | 2023 |
| KFH Accounting Ltd | Professional & scientific | 2014 |
| KFRD54 Holdings Limited | Financial services | 2024 |
| KFS Associates Ltd | Administrative & support | 2023 |
| KHE Fong Grandeur Ltd | Water & waste | 2025 |
| Kickback Kampers Ltd. | Administrative & support | 2021 |
| Kiln Supply Services Limited | Wholesale & retail | 1980 |
| Kinect Services Limited | Transport & logistics | 2013 |
| Kinfield Limited | Other services | 1986 |
| King Overseas Limited | Administrative & support | 2020 |
| Kingsfold Developments Ltd | Construction | 2017 |
| Kinology Agency Ltd | Professional & scientific | 2024 |
| Kinray Consulting Ltd | Administrative & support | 2015 |
| Kirolar Limited | Other services | 2026 |
| Kirstybowks Bespokes Ltd | Arts & recreation | 2022 |
| Kisaeng Limited | Administrative & support | 2006 |
| Kittay Ltd | Administrative & support | 2023 |
| KJH Contractors Limited | Construction | 1997 |
| KL Health Limited | Other services | 2024 |
| KL Plumbing and Heating Solutions Ltd | Construction | 2017 |
| KM Buildcheck Limited | Professional & scientific | 2026 |
| Kmbm Construction Ltd | Construction | 2026 |
| Knights Kennels Limited | Other services | 2015 |
| KNZ Footcare Ltd | Health & social care | 2019 |
| Kollective Design Limited | Professional & scientific | 2024 |
| Kolodev Ltd | Information & communication | 2021 |
| Kratz Limited | Construction | 2016 |
| KRI Property Limited | Real estate | 2024 |
| KS Autos (Essex) Ltd | Wholesale & retail | 2026 |
| KSD Marketing Consultants Ltd | Professional & scientific | 2025 |
| KSN Elite Ltd | Education | 2016 |
| KYM Fastfood Ltd | Hospitality | 2018 |
| L a Lounge Limited | Other services | 2023 |
| L F Building & Maintenance Ltd | Construction | 2022 |
| L Nash Ltd | Financial services | 2024 |
| L Wells Holdings Limited | Financial services | 2024 |
| L&B Media Limited | Information & communication | 2024 |
| L.B.S. Restoration Limited | Wholesale & retail | 2018 |
| L.K. Roofs Ltd | Construction | 2025 |
| L.T. Heating Services Limited | Construction | 2003 |
| LA FAM Homes Ltd | Real estate | 2019 |
| LAB Essex Limited | Wholesale & retail | 2022 |
| Lady Landlords Ltd | Households | 2015 |
| Lailen Property Services Limited | Real estate | 2021 |
| LAN Technical Solutions Limited | Information & communication | 2014 |
| Landscape Oak LOS Limited | Professional & scientific | 2026 |
| Laotek Limited | Information & communication | 2007 |
| Lapart Ltd | Real estate | 2016 |
| Larkin & Bailey Ventures Ltd | Wholesale & retail | 2022 |
| Larkspur Group Ltd | Administrative & support | 2023 |
| Laser Essex Holdings Limited | Financial services | 2016 |
| Laserline Automotive Ltd | Wholesale & retail | 2013 |
| Lash-Hart Ltd | Other services | 2017 |
| Lashi Contractors Ltd | Construction | 2021 |
| Latc Ltd | Real estate | 2015 |
| Laura Ellen Mortgage Advice Limited | Financial services | 2026 |
| Lawrence Antony Homes Limited | Real estate | 2012 |
| Lazy Day Goods Limited | Wholesale & retail | 2023 |
| LB Automotives Limited | Wholesale & retail | 2026 |
| LB Financial Limited | Financial services | 2017 |
| LBF Properties Limited | Real estate | 2020 |
| Lbollu Limited | Information & communication | 2025 |
| Lcbf Realisation Limited | Hospitality | 2013 |
| LE Prairie Childcare Ltd | Health & social care | 2020 |
| Leach Development and Innovation Ltd | Construction | 2018 |
| Leadr Marketing Limited | Professional & scientific | 2023 |
| Lece Accounting Limited | Professional & scientific | 2020 |
| Lece Bookkeeping Services Limited | Professional & scientific | 2016 |
| LEE Pool Ltd | Construction | 2025 |
| Leech's Cleaning Services Limited | Administrative & support | 2003 |
| Leed Digital Ltd | Professional & scientific | 2014 |
| Leetan Limited | Construction | 2017 |
| Legacy Lane Investments Ltd | Real estate | 2022 |
| Legacy Property Solutions Limited | Real estate | 2016 |
| Leigh Drone Surveying Limited | Professional & scientific | 2025 |
| Leigh Electrical Controls (UK) Limited | Manufacturing | 2006 |
| Leigh Road Developments Ltd | Real estate | 2021 |
| Leigh Scaffolding Services Limited | Construction | 2000 |
| Lemon Lizard Limited | Real estate | 2013 |
| Lemsford Mill Controls Limited | Manufacturing | 1999 |
| Leonard Dance Productions Ltd | Arts & recreation | 2025 |
| Lesevi Limited | Transport & logistics | 2013 |
| Letting Pro Limited | Households | 2024 |
| Leveche Developments Limited | Construction | 2014 |
| Lewbo Ltd | Financial services | 2024 |
| Lgordon Services Ltd | Other services | 2011 |
| Liam Brazier Illustration & Animation Limited | Professional & scientific | 2012 |