| Laatukaasu Oy | Construction | 2017 |
| Laatukattila Oy | Manufacturing | 1953 |
| Laatulaasti Oy | Construction | 2024 |
| Laatupeite Oy | Manufacturing | 2004 |
| Laatusepät Oy | Construction | 2023 |
| Laatusähkäri Oy | Construction | 2014 |
| Laatutekstit Kari Pitkänen Oy | Arts & recreation | 1992 |
| Laatutoimisto Proce Ky | Professional & scientific | 1995 |
| Laavat Oy | Information & communication | 2017 |
| Labaduu Productions Oy | Professional & scientific | 2009 |
| LabelMat Oy | Wholesale & retail | 2026 |
| Labilo Oy | Wholesale & retail | 2014 |
| Labwise Oy | Information & communication | 2004 |
| Lacum Oy | Real estate | 2015 |
| Lada Productions Oy | Professional & scientific | 2021 |
| Lady of the Baltic Sea Oy | Administrative & support | 2006 |
| Lago Networks Oy | Information & communication | 2013 |
| Lagoon Fish Foot Spa Oy | Other services | 2011 |
| Lahden Essetko Oy | Real estate | 1988 |
| Lahden Koukkuravintolat Oy | Hospitality | 2022 |
| Lahdesjärven Säätövoima Oy | Professional & scientific | 2022 |
| Laihian Hyvinvointi Oy | Health & social care | 2018 |
| Lainappi Oy | Information & communication | 2020 |
| Laine Flow Oy | Other services | 2020 |
| Laine Publishing Oy | Information & communication | 2017 |
| LainePro Oy | Administrative & support | 2007 |
| Laipio Oy | Construction | 2024 |
| Laitehuolto Pumppumestarit Oy | Manufacturing | 2019 |
| Laitepalvelu Jorma Juselius Oy | Construction | 1983 |
| Laitila Arkkitehdit Oy Tampere | Professional & scientific | 2000 |
| Laitix Oy | Health & social care | 2009 |
| Laiturimestarit, Haurunen & Laakso | Construction | 1990 |
| Laivaosakeyhtiö Intti | Administrative & support | 1997 |
| Lakalaivan Autotalo Oy | Financial services | 1989 |
| Lakalaivan Pesupiste Ky | Other services | 1998 |
| Lake Bros Holdings OY | Professional & scientific | 2021 |
| Lakea Film Company osk | Professional & scientific | 2016 |
| Lakeframe Oy | Information & communication | 2023 |
| Lakeland Accounting Oy | Professional & scientific | 2023 |
| Lakeside Invest Oy | Real estate | 1998 |
| Lakeuden Malmi Oy | Professional & scientific | 2020 |
| Laki Luoto Ky | Professional & scientific | 2014 |
| Lakiasiaintoimisto A. Heikkilä & Co Oy | Professional & scientific | 1995 |
| Lakiasiaintoimisto Aaro Hämäläinen Oy | Professional & scientific | 2017 |
| Lakiasiaintoimisto Berglund Oy | Professional & scientific | 2008 |
| Lakiasiaintoimisto Borgenström Oy | Professional & scientific | 2015 |
| Lakiasiaintoimisto Heikkilä, Leinonen & Co Oy | Professional & scientific | 2002 |
| Lakiasiaintoimisto Legalex Oy | Professional & scientific | 2016 |
| Lakiasiaintoimisto Mikko Rantanen Oy | Professional & scientific | 2023 |
| Lakiasiaintoimisto Määttä Oy | Professional & scientific | 2021 |
| Lakiasiaintoimisto Naskali Oy | Professional & scientific | 2021 |
| Lakiasiaintoimisto Otso Oy | Professional & scientific | 2021 |
| Lakiasiaintoimisto Pykälänikkari Ky | Professional & scientific | 2001 |
| Lakiasiaintoimisto Räikkä Oy | Professional & scientific | 2025 |
| Lakiasiaintoimisto Vesa Pajunen Oy | Professional & scientific | 1985 |
| Lakitalo Forum Oy | Real estate | 2019 |
| Lakitalo Holding Oy | Financial services | 2019 |
| Lakitilitoimisto Oy | Professional & scientific | 1994 |
| Lakitoimisto Pirkka Lappalainen Ky | Professional & scientific | 1997 |
| Lakitoimisto Tiina Tikka Oy | Professional & scientific | 1996 |
| Lakonia Clothing Oy | Wholesale & retail | 2021 |
| Lama Capital Oy | Real estate | 2026 |
| Lama Catering Oy | Hospitality | 2025 |
| Lamcom Oy | Wholesale & retail | 2015 |
| Lame & Valju Oy | Wholesale & retail | 2024 |
| Lamina Holding Oy | Professional & scientific | 2018 |
| Lammela Consulting Oy | Professional & scientific | 2017 |
| Lamminpään Perhekoti Oy | Health & social care | 2026 |
| Lamminpään Puutarha Oy | Wholesale & retail | 2007 |
| Lamminranta Group Oy | Professional & scientific | 2021 |
| Lamnia Oy | Health & social care | 2009 |
| Lamrav Oy | Hospitality | 2021 |
| LanWorld Finland Oy | Information & communication | 1984 |
| Lana kebab pizzeria Oy | Hospitality | 2026 |
| Landlady Oy | Real estate | 2006 |
| Lane Care Oy | Manufacturing | 2011 |
| Lanisaon Oy | Financial services | 2025 |
| Lankameri Oy | Wholesale & retail | 2025 |
| Lankarulla Foods Oy | Other services | 2026 |
| Lankinen Consulting Oy | Financial services | 2006 |
| Lankinen Palvelut Oy | Professional & scientific | 2017 |
| Lanopa Oy | Wholesale & retail | 1996 |
| Lantto Korporaatio Ky | Arts & recreation | 2011 |
| Lapinlahden Uniikkikaluste Oy | Manufacturing | 1996 |
| Lapinsetä Oy | Hospitality | 2025 |
| Lapis Rakennus Holding Oy | Professional & scientific | 2011 |
| Lapis Rakennus Oy | Construction | 2006 |
| Lapland Brothers Avoin Yhtiö | Wholesale & retail | 2017 |
| Laplevi Oy | Real estate | 2019 |
| Lappalainen & CO Oy | Administrative & support | 2025 |
| Lappalainen Holding Oy | Financial services | 2025 |
| Lappispola Oy | Real estate | 1984 |
| Lapple Group Oy | Professional & scientific | 2023 |
| Lapps Oy | Information & communication | 2019 |
| Lapuan TPV Oy | Wholesale & retail | 1993 |
| Lari Montonen Oy | Hospitality | 2006 |
| Larm Marketing Oy | Professional & scientific | 2013 |
| Laroseal Oy | Health & social care | 2023 |
| Las Duras Oy | Education | 2020 |
| Lasele Oy | Wholesale & retail | 2008 |