| Kuljetus Reijo Mecklin Oy | Transport & logistics | 1999 |
| Kuljetus Risto Sydänmaa Oy | Transport & logistics | 1998 |
| Kuljetus S. Silen Oy | Transport & logistics | 2006 |
| Kuljetus Sundell Oy | Transport & logistics | 2002 |
| Kuljetus Suutarinen Oy | Transport & logistics | 2012 |
| Kuljetusliike Ikävalko Oy | Transport & logistics | 1967 |
| Kuljetusliike M.Laitinen Oy | Transport & logistics | 2021 |
| Kuljetusliike P. Lindström Oy | Transport & logistics | 2009 |
| Kuljetusliike Pekki Oy | Transport & logistics | 2018 |
| Kuljetusliike Rafael Danielsson & Kumpp. Ky | Transport & logistics | 1974 |
| Kuljetusliike Raimo Saarela Oy | Transport & logistics | 1977 |
| Kulta Kirppari Oy | Wholesale & retail | 2022 |
| Kultapalikat Oy | Hospitality | 2008 |
| Kultavilla Oy | Manufacturing | 2013 |
| Kuntokartoitus ja Rakennuspalvelu Eksa Oy | Professional & scientific | 1993 |
| Kuntun Lähiliha Oy | Manufacturing | 2013 |
| Kuohu Invest Oy | Financial services | 2024 |
| Kurjenpolvi Oy Espoo | Administrative & support | 2014 |
| KustannusAika Oy | Professional & scientific | 2024 |
| Kuva Koistinen Ky | Wholesale & retail | 1955 |
| Kuvauskaksikko Oy | Professional & scientific | 2014 |
| Kuzu Side Oy | Hospitality | 2020 |
| Kylmäkuu Film Co. Oy | Information & communication | 2021 |
| Kylmätech Oy | Construction | 2020 |
| Käännöstoimisto Marianne Saari Oy | Professional & scientific | 1988 |
| L & L Mechatronics Oy | Professional & scientific | 1994 |
| L-Automation Oy | Construction | 2016 |
| LB2 Living Oy | Arts & recreation | 2015 |
| Live Well OY | Administrative & support | 2017 |
| LL-louhinta Oy | Construction | 2023 |
| LM Förvaltning Ab | Professional & scientific | 2016 |
| LO-putki oy | Construction | 2021 |
| LRS Management Oy | Professional & scientific | 2016 |
| LS Kodit Oy | Construction | 2011 |
| LSA Systems Oy | Construction | 2009 |
| LT-Tuote Oy | Wholesale & retail | 1989 |
| Luolan Lasi & Asennuspalvelu OY | Construction | 2011 |
| LUSP Kiinteistöt Oy | Real estate | 2012 |
| LUVYLab Oy Ab | Professional & scientific | 2018 |
| LVI Savaloja Oy | Construction | 2021 |
| LVI-Asennus AJL Oy | Construction | 2020 |
| LVI-Jaheka Ky | Construction | 1992 |
| LVI-Line Oy | Construction | 2014 |
| LVI-Make Oy | Construction | 2016 |
| LVI-Malmberg Oy | Construction | 2017 |
| LVI-Parviainen Oy | Construction | 2000 |
| LVI-Sampo Oy | Construction | 2018 |
| LVI-Tekniikka VEST Oy | Construction | 2024 |
| LVI-toimisto Ca-Se-Ma Oy | Professional & scientific | 1986 |
| LVK Consulting Oy | Professional & scientific | 2025 |
| Laakso-Viertiö Oy | Hospitality | 2023 |
| Laatoitus Juha Reinikainen Oy | Construction | 2000 |
| Laatubuukki Oy | Professional & scientific | 2019 |
| Laiskat Pojat Oy | Construction | 2025 |
| Lakeplay Capital Oy | Financial services | 2024 |
| Lakeside Resort Lohja Oy | Hospitality | 2009 |
| Lakiasiat Petter Kavonius Ky | Professional & scientific | 1989 |
| Lape Saneeraus Oy | Construction | 2022 |
| Laroc Oy | Construction | 2007 |
| Lasse Sutinen Oy | Administrative & support | 2022 |
| LatvaRak Oy | Construction | 2016 |
| Lauwers Oy | Construction | 2025 |
| Lazy chicken oy | Hospitality | 2025 |
| LeasIT Oy | Information & communication | 2002 |
| Lecon Oy | Professional & scientific | 2010 |
| Lego Mika Oy | Arts & recreation | 2019 |
| Lehmijärven Romu ja Rauta Oy | Wholesale & retail | 1977 |
| Lehmussilta Oy | Agriculture & fishing | 2023 |
| Lehto Medical Oy | Health & social care | 2020 |
| Leijonakatsastus Oy | Professional & scientific | 2014 |
| Leipomo J. W. Virtanen Oy | Manufacturing | 1978 |
| Lejonkraft oy | Construction | 2024 |
| Lempolan autohuolto Oy | Other services | 2020 |
| Leo Nieminen & Knit Ky | Construction | 1972 |
| Lepolanmäen Kiinteistö ja Huolto Oy | Construction | 2020 |
| Lepoon Oy | Other services | 2020 |
| Levare Oy | Transport & logistics | 2025 |
| Levula Oy | Arts & recreation | 2023 |
| Lexer OY | Construction | 2012 |
| Lidab Finland Oy | Wholesale & retail | 2002 |
| Life Care Finland Oy | Agriculture & fishing | 2002 |
| Light Laskutuspalvelut Oy | Administrative & support | 2023 |
| Lii Capital Oy | Professional & scientific | 2017 |
| Liikkula Oy | Arts & recreation | 2021 |
| Liikunta ja hyvinvointikeskus Aplico Oy | Arts & recreation | 2004 |
| Liitoon Oy | Professional & scientific | 2026 |
| Lilikoi Oy | Professional & scientific | 2025 |
| Liman Rakennuspalvelut Oy | Construction | 2022 |
| Lindbergin Liiketilat Oy | Real estate | 2009 |
| Linmer Lohja Oy | Real estate | 1982 |
| Linnais-Puistolan Huolto Oy | Administrative & support | 1971 |
| Linnéa Borealis Redivivus Oy | Other services | 1989 |
| Linrei Oy | Professional & scientific | 1993 |
| Lipponen Kiinteistöt Oy | Professional & scientific | 2019 |
| Load Science Oy | Information & communication | 2026 |
| LogopediCare Oy | Health & social care | 2017 |
| LohjaKey Oy | Real estate | 2025 |
| Lohjan AHA palvelut Oy | Construction | 2020 |
| Lohjan AJT-Yhtiöt Oy | Construction | 2019 |
| Lohjan AS-Koneistus Oy | Manufacturing | 1995 |