| Key Performance International Recruitment Limited | Administrative & support | 2016 |
| Keybridge IT Solutions Ltd | Information & communication | 2010 |
| Keyline Couriers Ltd | Transport & logistics | 2026 |
| Keys (Bexleyheath) Limited | Wholesale & retail | 2010 |
| Khabra Property Investments Ltd | Real estate | 2023 |
| Khakh Properties Limited | Real estate | 2023 |
| Khristian Management LLP | | 2020 |
| Khushi Construction Ltd | Construction | 2013 |
| Khushiyan Ltd | Real estate | 2019 |
| Kicking IT Global Ltd. | Education | 2018 |
| KIM Associates Limited | Health & social care | 2014 |
| Kimble Digital Ltd | Professional & scientific | 2026 |
| Kindscare Ltd | Health & social care | 2020 |
| Kinfauns Road (Block a) Management Company Limited | Professional & scientific | 1992 |
| Kinfauns Road (Block C) Management Company Limited | Professional & scientific | 1992 |
| Kinfauns Road (Block E) Management Company Limited | Households | 1992 |
| Kinfauns Road (J Block) Management Ltd | Households | 2021 |
| Kingdom Love Outreach CIC | Health & social care | 2023 |
| Kinsway Property Management Limited | Real estate | 2024 |
| Kkmb UK Ltd | Real estate | 2014 |
| KKP Estates Limited | Real estate | 2017 |
| Kksc Services Ltd | Health & social care | 2023 |
| Klevor Limited | Information & communication | 2025 |
| KLM Studios Limited | Arts & recreation | 2025 |
| KMR IT Solutions Ltd | Information & communication | 2016 |
| Knight and Grace Legal Services Limited | Professional & scientific | 2025 |
| Knightsbridge Facilities Ltd | Manufacturing | 2017 |
| Knob and Keys Ltd | Real estate | 2022 |
| Koala.Au Ltd | Construction | 2020 |
| Kodaaron Limited | Real estate | 2024 |
| Koded IT Ltd | Information & communication | 2022 |
| Koinonia Care Ltd | Health & social care | 2025 |
| Koksons Services Limited | Administrative & support | 2018 |
| Kolbre Builders Ltd | Construction | 2024 |
| Korabi Ltd | Hospitality | 2025 |
| Koradi Limited | Construction | 2016 |
| Kotoy Trans Ltd | Transport & logistics | 2022 |
| KP Optical Ltd | Other services | 2010 |
| KP Renewables Ltd | Construction | 2025 |
| KPC Catering Ltd | Hospitality | 2025 |
| KR Imaging Limited | Health & social care | 2026 |
| KR MR Management Limited | Real estate | 2026 |
| Krda Limited | Real estate | 2025 |
| KRE Building Limited | Other services | 2019 |
| Kreglex Productions and Concerns Limited | Information & communication | 2026 |
| Krisha International Limited | Wholesale & retail | 2016 |
| Krystal Clear Cleaning Ltd | Households | 2017 |
| Ksar Group Limited | Hospitality | 2022 |
| KSB Home Improvements Limited | Construction | 2009 |
| Kshiptech Ltd | Information & communication | 2023 |
| KSP Finance Ltd | Professional & scientific | 2012 |
| Kulvinder K. Shokar Limited | Financial services | 2022 |
| Kundi Consulting Limited | Professional & scientific | 2008 |
| KW RX Limited | Health & social care | 2025 |
| L & H Mulligan Ltd | Other services | 2023 |
| L D Food Ingredients Ltd | Wholesale & retail | 2010 |
| L&Ao Care Services Limited | Health & social care | 2014 |
| L.M.G. (Kent) Limited | Wholesale & retail | 1988 |
| LA Services ( South East) Ltd | Construction | 2021 |
| LAC Finance Ltd | Professional & scientific | 2024 |
| Lacuna London Ltd | Professional & scientific | 2016 |
| LAD Distribution Ltd | Transport & logistics | 2023 |
| Lakefern Limited | Construction | 2016 |
| Lakhey Ltd | Real estate | 2025 |
| Lakij Healthcare Ltd | Health & social care | 2024 |
| Lala Contractors Ltd | Construction | 2015 |
| Lall Building Services Ltd | Construction | 2025 |
| Lanceauto Limited | Wholesale & retail | 2021 |
| Larry Says ALL Limited | Other services | 2026 |
| Laser Brand Limited | Wholesale & retail | 2017 |
| Laser Ticketing Systems Limited | Information & communication | 1988 |
| Latch Eco Limited | Administrative & support | 2017 |
| Laver Construction Limited | Construction | 2012 |
| Lawgical Solutions Ltd | Information & communication | 2024 |
| Lawnscape Services Ltd | Administrative & support | 2015 |
| Lawta Ltd | Construction | 2023 |
| Layos Ltd | Wholesale & retail | 2025 |
| LCS Surveyors Ltd | Real estate | 2014 |
| Lead Elements Ltd | Construction | 2022 |
| League Property Services Ltd | Administrative & support | 2005 |
| Lebanese Palace Ltd | Hospitality | 2025 |
| Legal Protect UK Limited | Professional & scientific | 2011 |
| Legal Protect Willcare Limited | Professional & scientific | 2011 |
| Legal Translations Limited | Professional & scientific | 2001 |
| Leggtech Ltd | Information & communication | 2023 |
| Lemami Limited | Health & social care | 2015 |
| Lemon Emporio Ltd | Wholesale & retail | 2025 |
| Leng Production Ltd | Manufacturing | 2025 |
| LEO ALB Ltd | Construction | 2023 |
| LEO Tam's Limited | Health & social care | 2013 |
| Letanpro Ltd | Professional & scientific | 2026 |
| Level 33 Limited | Manufacturing | 2025 |
| Level Design Agency Ltd | Information & communication | 2022 |
| Lexacode Ltd | Information & communication | 2025 |
| Lexxsign Ltd | Information & communication | 2026 |
| Lfccatering Ltd | Hospitality | 2025 |
| LGT Electrical Ltd | Construction | 2021 |
| Lhotse Properties Limited | Real estate | 2018 |
| Liam Property Ltd | Real estate | 2024 |
| Liberty Infrastructure Company Limited | Professional & scientific | 2018 |