| Kuljetus Maliniemi Oy | Transport & logistics | 1993 |
| Kuljetus Raimo Alalahti Oy | Transport & logistics | 2001 |
| Kuljetus- ja Nosto Niskanen Oy | Transport & logistics | 1991 |
| Kuljetusliike Kuure avoin yhtiö | Transport & logistics | 2021 |
| Kuljetusliike Seppo Oikarinen Ky | Transport & logistics | 2006 |
| Kuljetusliike Ville Purra Oy | Transport & logistics | 1999 |
| Kuljunkorva Oy | Construction | 2010 |
| Kultareservi Holding Oy | Financial services | 2023 |
| Kumikko Oy | Wholesale & retail | 2018 |
| Kuntosali Body Center Oy | Arts & recreation | 2006 |
| Kuusirati Oy | Agriculture & fishing | 2024 |
| KvistTech Oy | Manufacturing | 2025 |
| Kymppihalli Oy | Real estate | 1984 |
| LAPMAC Oy | Other services | 2010 |
| Lappiahalli OY | Arts & recreation | 2008 |
| LB-kiinteistöt Oy | Real estate | 2025 |
| LETTnordic Oy | Wholesale & retail | 2016 |
| LK Engineering Oy | Professional & scientific | 2005 |
| LKE Group Oy | Financial services | 2020 |
| LP Lakkapää Oy | Wholesale & retail | 2010 |
| LP-Garden Oy | Manufacturing | 2022 |
| LTMS (Let The Music Speak) Kommandiittiyhtiö | Professional & scientific | 2011 |
| LVI VäKi Oy | Construction | 2022 |
| LVI-Asennus Pesonen Ky | Construction | 1990 |
| LVI-Palvelu Pekka Hooli Ky | Construction | 2001 |
| LVI-Pitkälä Lappi Oy | Construction | 2018 |
| LVI-Pukema Oy | Construction | 2021 |
| Lynqore OY | Information & communication | 2025 |
| Laine Media Oy | Professional & scientific | 2023 |
| Lakeva Oy | Manufacturing | 2003 |
| Laki- ja rakentamispalvelut PrivaLex Oy | Professional & scientific | 2007 |
| Lakiasiaintoimisto Markku Lahdenperä Ky | Professional & scientific | 2012 |
| Lakkapää Import Oy | Wholesale & retail | 2018 |
| Lapin Autokauppa Oy | Wholesale & retail | 2017 |
| Lapin Elementtiasennus Oy | Manufacturing | 2011 |
| Lapin Graf Mark Ky | Professional & scientific | 1988 |
| Lapin Kalustepuusepät Ky | Manufacturing | 1991 |
| Lapin Konehuolto Ky | Other services | 2014 |
| Lapin Kunnossapito Oy | Wholesale & retail | 2013 |
| Lapin Lomarakennus Oy | Construction | 2005 |
| Lapin Muuraus- ja Rakennuspalvelu Oy | Construction | 2021 |
| Lapin Palkinen Oy | Administrative & support | 2007 |
| Lapin RVP Oy | Real estate | 2020 |
| Lapin Rakennus Palvelu Oy | Construction | 1992 |
| Lapin Raudoitus ja Rakennus Oy | Construction | 2020 |
| Lapin Taide ja Lahja Oy | Wholesale & retail | 1981 |
| Lapin Toimistokone Oy | Wholesale & retail | 1976 |
| Lapin WeldMet Oy | Construction | 2008 |
| Lapland River Oy | Hospitality | 2021 |
| Lappi Padel Oy | Arts & recreation | 2019 |
| LappiClean Oy | Administrative & support | 2025 |
| Lappia-Koulutus Oy | Education | 1995 |
| Lapur Tekniikka Oy | Construction | 2018 |
| Lastenvaateliike Akseliinus Oy | Wholesale & retail | 2023 |
| Lehtopojat Oy | Agriculture & fishing | 2007 |
| LeiKon Lahti Oy | Construction | 2007 |
| Lepola Group Oy | Administrative & support | 2025 |
| Levilinna Oy | Real estate | 1988 |
| Liakka City Invest Oy | Financial services | 2025 |
| Liidia Co Oy | Construction | 2020 |
| Liikenneyhtiö Janne Moisanen Oy | Transport & logistics | 1999 |
| Liikenneyhtiö Olavi Aho Oy | Transport & logistics | 1971 |
| Lilium Oy | Professional & scientific | 2018 |
| LillaBeth Ky | Education | 1996 |
| Linda Golf Ky | Education | 2011 |
| Lingsom Oy | Information & communication | 2019 |
| Logora Oy | Professional & scientific | 2019 |
| Lokkisaari Holding Oy | Financial services | 1973 |
| Lomakan Sähkö Ky | | 1977 |
| Lomalompolo Oy | Real estate | 1989 |
| Lord Garage Oy | Other services | 2026 |
| Loumari Ky | Manufacturing | 1987 |
| Lucone Finland Oy | Wholesale & retail | 2008 |
| Lukkarila & Mustajärvi avoin yhtiö | Administrative & support | 2014 |
| Lukko Partanen Oy | Construction | 2017 |
| Lvi Marjeta Oy | Construction | 2018 |
| Lvi Timo Pohjola Oy | Construction | 2007 |
| Lvi-Suunnittelu Pohjola Oy | Professional & scientific | 2022 |
| Lvi-Vanhatalo Oy | Construction | 1989 |
| Lämpötori Oy | Wholesale & retail | 2020 |
| Länsi-Pohjan Kone Oy | Wholesale & retail | 2005 |
| Länsi-Pohjan Yrityspalvelu Oy | Professional & scientific | 1994 |
| Länsipohjan Hevosurheilukeskus Oy | Arts & recreation | 1974 |
| Länsirajan Auto Oy | Wholesale & retail | 2020 |
| Lääkkölä Oy | Construction | 2026 |
| M Hirsikangas Ky | Transport & logistics | 1995 |
| M&B Palvelut Oy | Construction | 2022 |
| M&S Tirkkonen Ky | Construction | 1995 |
| M-Carpet Avoin yhtiö | Manufacturing | 2003 |
| M. Huhtalo Oy | Wholesale & retail | 1994 |
| Maanrakennus Ari Mattinen OY | Construction | 2011 |
| Majoituspalvelut Vok OY | Hospitality | 1996 |
| Markon Kone OY | Manufacturing | 2008 |
| MHK-Service Oy | Manufacturing | 2005 |
| MJ-Rakennus Oy | Construction | 2024 |
| ML Installation Oy | Manufacturing | 2024 |
| MPT Service Oy | Manufacturing | 2010 |
| MQJ-Rakentajat Oy | Construction | 2011 |
| MR Car Detailing Oy | Other services | 2023 |
| MTO Holding Oy | Financial services | 2025 |