| Lasita Oy | Wholesale & retail | 2022 |
| Lasiturva Oy | Other services | 2025 |
| Lasitusliike Tuhat Ikkunaa Oy | Construction | 1992 |
| Lasitusliike V Aalto Oy | Construction | 1990 |
| Lasitustalo Uuksulainen Oy | Financial services | 2020 |
| Lasityö Rantanen Oy | Construction | 1944 |
| Laskenta Ecumar Oy | Professional & scientific | 1990 |
| Laskenta Oy Tuula Kemiläinen | Professional & scientific | 1988 |
| Laskenta Vaskivuori Oy | Professional & scientific | 2004 |
| Laskenta ja sijoitus Paula & Kari Oy | Professional & scientific | 1999 |
| Laskentaforum Oy | Professional & scientific | 1987 |
| Laskentakolmio Oy | Financial services | 1987 |
| Laskentakuutio Oy | Professional & scientific | 2005 |
| Laskentapaja Oy | Professional & scientific | 2021 |
| Laskentatech Oy | Financial services | 2025 |
| Laskentaväline Oy | Wholesale & retail | 1971 |
| Laskos Virtuals Oy | Information & communication | 2021 |
| Laskukassa Oy | Financial services | 2012 |
| Laskutuspalvelu Kahiseva Oy | Professional & scientific | 2014 |
| Lasonki Oy | Construction | 2022 |
| Lasonpalo Music Oy | Arts & recreation | 2025 |
| Lasotech Oy | Wholesale & retail | 2015 |
| Lassen Autokoulu Oy | Education | 1966 |
| Lassi Lindfors & Co Oy | Transport & logistics | 1962 |
| Lassi Meronen Mountain Experience Oy | Education | 2024 |
| Lassi Sarvikivi Oy | Transport & logistics | 1995 |
| Lassila & Tikanoja Oyj | Water & waste | 2025 |
| Lassilan Autopiiri Oy | Real estate | 1979 |
| Lassin Kirjanpito Oy | Professional & scientific | 2025 |
| Lassin Paja Ky | Wholesale & retail | 2011 |
| Lassin Palvelut Oy | Arts & recreation | 2017 |
| Lasso Entertainment Oy | Arts & recreation | 2015 |
| Lasso Outfitter Oy | Wholesale & retail | 2024 |
| Last Laugh Productions osk | Professional & scientific | 2017 |
| Last Man Standing Oy | Arts & recreation | 2007 |
| Last Splash Consulting Oy | Information & communication | 2009 |
| Last Tuesday Oy | Professional & scientific | 2017 |
| Lasten Päiväkoti Omppu Oy | Education | 2001 |
| Lasten Päiväkoti Sinikello Oy | Education | 1989 |
| Lasten Salkku Oy | Financial services | 1993 |
| Lasten allergiaklinikka Oy Rosavilla Ab Allergikliniken för | Health & social care | 1997 |
| Lastenakatemia Oy | Education | 2016 |
| Lastenmaa OY | Information & communication | 2014 |
| Lastenpuoti Keinuhevonen Oy | Wholesale & retail | 2010 |
| Lastensuojelu Hilla Oy | Health & social care | 2025 |
| Lastenvanilja Kommandiittiyhtiö Keto | Wholesale & retail | 1977 |
| Lastrans Oy | Transport & logistics | 2023 |
| Lasuuri Ky | Other services | 2011 |
| Lataamo Group Oy | Professional & scientific | 2001 |
| LatausPolku Oy | Manufacturing | 2019 |
| Latauskumppanit Oy | Construction | 2026 |
| Late Group Oy | Professional & scientific | 2017 |
| Late Lunch Nova Oy | Hospitality | 2018 |
| Latennis Oy | Education | 2024 |
| Latent Research Ab | Information & communication | 2026 |
| Lateral Questions Oy | Information & communication | 2022 |
| Latgopalvelut Oy | Information & communication | 2019 |
| Latifundium Wald I Oy | Agriculture & fishing | 2012 |
| Latimmier Oy | Manufacturing | 2021 |
| Latino Suave Oy | Hospitality | 2026 |
| Latokartanon Pysäköinti Oy | Transport & logistics | 1997 |
| Lator Oy | Wholesale & retail | 2022 |
| Latte's Desire Oy | Information & communication | 2020 |
| Latte's Dream Oy | Information & communication | 2020 |
| Latteps Nord Oy | Construction | 2018 |
| Lattia-asennus Leinonen Oy | Construction | 2008 |
| Lattiakolmio Oy | Construction | 1989 |
| Lattiatohtori Oy | Construction | 2015 |
| Lattiatyö Moilanen Oy | Construction | 1994 |
| Lattiatyö Salmela Oy | Construction | 2022 |
| Lattori Oy | Information & communication | 2025 |
| Latua Group Oy | Health & social care | 2015 |
| Laturila Oy | Wholesale & retail | 2024 |
| Latva Group Oy | Administrative & support | 2026 |
| Latva Partners Oy | Financial services | 2026 |
| Latva Saneeraus ja Rakennus Oy | Construction | 2021 |
| Latvanen Consulting Oy | Professional & scientific | 2023 |
| Latvaselkä Wind Farm Oy | Energy | 2024 |
| Latvatähti Oy | Professional & scientific | 1998 |
| Latvus Oy | Real estate | 2023 |
| Latvusto Oy | Financial services | 2016 |
| Lauandi Oy | Other services | 2021 |
| Laude Spaces Oy | Arts & recreation | 2025 |
| Laudent Oy | Health & social care | 2017 |
| Laudre Holding Oy | Professional & scientific | 2015 |
| Laudre Nordic Oy | Construction | 2025 |
| Laueli Oy | Health & social care | 2020 |
| Laughing Gull Oy | Professional & scientific | 2018 |
| Lauhaus Oy | Arts & recreation | 2025 |
| Lauka Holding Oy | Financial services | 2025 |
| Laukaan Fysioterapia Oy | Health & social care | 2015 |
| Laukaan Terveyspalvelut Oy | Health & social care | 2006 |
| Laukkoski Investment & Leasing Corporation Oy | Administrative & support | 2017 |
| Laula Live Oy | Arts & recreation | 2019 |
| Laulau Oy | Education | 2008 |
| Laulava Lohi Oy | Hospitality | 2025 |
| Laulutaiteen ja -tieteen keskus Oy | Education | 2024 |
| LaumaDesign Oy | Professional & scientific | 2018 |
| Launch & Scale Oy | Financial services | 2021 |
| LaunchLoop Oy | Professional & scientific | 2025 |