| Little Buck Oy | Financial services | 2017 |
| Littoisten Aluelämpö Oy | Administrative & support | 1996 |
| Littoisten Liikenneasema OY | Real estate | 2009 |
| Live Edge Woodworking Oy | Manufacturing | 2020 |
| Live Exit Games Oy | Arts & recreation | 2015 |
| Lived myynti Oy | Wholesale & retail | 2025 |
| Living Trade Finland Oy | Construction | 2019 |
| LizArtWorks Finland Oy | Wholesale & retail | 2024 |
| Ljusström Kapital Oy | Financial services | 2015 |
| Lmax Oy | Manufacturing | 2021 |
| Lmoi Oy | Manufacturing | 2025 |
| Loadmanager Oy | Health & social care | 2020 |
| Lobo Group Oy | Construction | 2024 |
| Lock Kiinteistöt Oy | Real estate | 2025 |
| Loco Project Oy | Construction | 2014 |
| Lodge Rent Finland Oy | Real estate | 2019 |
| Log Master Oy | Information & communication | 2024 |
| LogiSystems Oy | Information & communication | 2016 |
| Logiskal Oy | Professional & scientific | 1993 |
| LogoHub Oy | Real estate | 2019 |
| Logoisat Kuntoutuspalvelut Oy | Health & social care | 2015 |
| Logomo Oy | Real estate | 2011 |
| Logomon tapahtumatilat Oy | Real estate | 2018 |
| Logpoint Oy | Wholesale & retail | 2005 |
| Lohikunta Oy | Manufacturing | 1975 |
| Lohivaara Ventures Oy | Financial services | 2023 |
| Lohko Holding Oy | Financial services | 2025 |
| Lohkotieto Oy | Financial services | 2022 |
| Loikka Care Oy | Information & communication | 2020 |
| Loipak Oy | Real estate | 2004 |
| Loiste Studiot Turku Oy | Education | 2025 |
| Loisto Siivouspalvelu Oy | Administrative & support | 2018 |
| Loiva Ratkaisut Oy | Professional & scientific | 2024 |
| Lola's Pizzeria Oy | Hospitality | 2023 |
| Loma-Caravan Oy | Administrative & support | 1985 |
| Loma-Hilappa Oy | Real estate | 1975 |
| Lomatti Oy | Real estate | 1974 |
| Lomavalkama Oy | Hospitality | 1967 |
| LonGame Oy | Real estate | 2018 |
| Longalba Oy | Professional & scientific | 2004 |
| Look at me Oy | Other services | 2020 |
| Loopie Foods Oy | Hospitality | 2021 |
| Looptec Software Oy | Information & communication | 2003 |
| Lopsi Ltd. Oy | Arts & recreation | 1994 |
| Lotta Suvanto Oy | Health & social care | 2023 |
| Louhelo Oy | Construction | 1978 |
| Louhevuori Oy | Professional & scientific | 1994 |
| Louhintaliike Mäkinen Oy | Construction | 1981 |
| Louhos Group Oy | Professional & scientific | 2016 |
| Louhos Management Oy | Professional & scientific | 2023 |
| Lounacom Oy | Information & communication | 2012 |
| Lounais - Suomen Taxidata Oy | Transport & logistics | 1992 |
| Lounais-Suomen Isännöinti Oy | Real estate | 1994 |
| Lounais-Suomen Jätehuolto Oy | Water & waste | 2003 |
| Lounais-Suomen Kaupunkikiinteistöt Oy | Real estate | 1988 |
| Lounais-Suomen Kiinteistösijoitus Ky | Real estate | 2015 |
| Lounais-Suomen Koti ja Asunto Ky | Real estate | 2017 |
| Lounais-Suomen Remonttipalvelu Oy | Real estate | 1991 |
| Lounais-Suomen Taksikoulutus Oy | Education | 2022 |
| Lounais-Suomen Talopalvelu Oy | Construction | 1998 |
| Lounais-Suomen Tietojakelu Oy | Transport & logistics | 2014 |
| Lounais-Suomen Vahinkoautokeskus Oy | Water & waste | 2001 |
| Lounais-Suomen vesi- ja ympäristötutkimus Oy | Professional & scientific | 1999 |
| Lounaisasunnot Oy | Real estate | 2014 |
| Lounas Manhattan Oy | Hospitality | 2026 |
| LounasRavintola Turku Metropol Oy | Hospitality | 2015 |
| Lounascenter Turku Oy | Hospitality | 2019 |
| Lounaspolku Oy | Hospitality | 2009 |
| Lounassatama Oy | Hospitality | 2019 |
| Lounge Turku Oy | Hospitality | 2025 |
| Love Company Oy | Financial services | 2020 |
| Lovely Living Oy | Real estate | 2022 |
| Lovira Oy | Wholesale & retail | 2018 |
| Lowell Investment Nordic Oy | Financial services | 2025 |
| Lowell Nordics Oy | Financial services | 2016 |
| Lowell Suomi Oy | Administrative & support | 1973 |
| LuXeko Brands Oy | Wholesale & retail | 2016 |
| Lubri Oy | Wholesale & retail | 2023 |
| Lucia Capital Oy | Financial services | 1991 |
| Lucius Fox KOy | Real estate | 2026 |
| Luckiest Group OY | Transport & logistics | 2026 |
| Lucky Frank Marketing OY | Professional & scientific | 2006 |
| Ludentia Oy | Arts & recreation | 2023 |
| LudiCreations Oy | Manufacturing | 2018 |
| Ludoful Oy | Information & communication | 2020 |
| Ludovico Oy | Financial services | 2021 |
| Luistintohtori oy | Wholesale & retail | 2024 |
| LukAd Oy | Information & communication | 2019 |
| Luka Holding Oy | Financial services | 2000 |
| Lukkotaiturit Oy | Wholesale & retail | 1989 |
| Lumari Global Oy | Professional & scientific | 2025 |
| Lumberloon Ab | Manufacturing | 2015 |
| Lumera Health Oy | Health & social care | 2025 |
| Lumeton Oy | Professional & scientific | 2018 |
| Lumo Keittiöt Oy | Wholesale & retail | 2015 |
| LumoMedia Oy | Professional & scientific | 2023 |
| Lumonia Clinic Oy | Health & social care | 2020 |
| Lumous Visio Oy | Information & communication | 2026 |
| Luna Ravintola Oy | Hospitality | 2025 |
| Lunadent OY | Manufacturing | 2010 |