| Lackcenter Kb | Construction | 1990 |
| Lager 157 Oy | Wholesale & retail | 2020 |
| Lager 43 Ab | Real estate | 2021 |
| Lagret AB | Real estate | 2020 |
| Lagurina Ab | Financial services | 1988 |
| Laltilis Oy | Wholesale & retail | 2007 |
| Landskapet Ålands pensionsfond Fastighetsförvaltning Ab | Real estate | 2012 |
| Lapin Aurora Oy | Transport & logistics | 2025 |
| Larstad Ab | Hospitality | 2017 |
| Laskea Consulting Ab | Professional & scientific | 2014 |
| Laurenz Ab | Health & social care | 2026 |
| Lawhill Ab | Financial services | 1985 |
| Lax & Axberg Ab | Professional & scientific | 2017 |
| Lead Invest Ab | Professional & scientific | 2007 |
| Leakomatic Ab | Manufacturing | 2002 |
| Lecapital Ab | Financial services | 1987 |
| Leftorium AB | Professional & scientific | 2020 |
| Leksakshuset Lekia Åland Ab | Financial services | 1994 |
| LekÅland Ab | Financial services | 2003 |
| Lemberg & Lemberg Ab | Real estate | 1986 |
| Lemeo Ab | Professional & scientific | 2019 |
| Lenstopia AB | Arts & recreation | 2021 |
| Lerita Ab | Financial services | 1987 |
| Leva BörMan Ab | Other services | 2020 |
| Lifax Ab | Professional & scientific | 2023 |
| Liftraser Ab | Professional & scientific | 2005 |
| Lignells Läkartjänst Ab | Health & social care | 2007 |
| Lillemor von Köhler Ålrit Ab | Professional & scientific | 1989 |
| Lillkringlan Ab | Manufacturing | 2022 |
| Lina Sandell Ab | Professional & scientific | 2015 |
| Lindan Ab | Real estate | 1993 |
| Lindberg & Lindberg öppet bolag | Wholesale & retail | 1991 |
| Lindqvist & Oivo Ab | Arts & recreation | 2016 |
| Lindro Konsult Ab | Professional & scientific | 2005 |
| Lindström Åland Ab | Other services | 1972 |
| Lindströms Fortune Ab | Other services | 2016 |
| Lingam Ab | Health & social care | 2015 |
| Lion Music Ab Ltd | Information & communication | 1989 |
| Lisco Bok och Papper Ab | Wholesale & retail | 2012 |
| Living V & I Ab | Other services | 1990 |
| Livning öppet bolag | Arts & recreation | 2006 |
| Livra Oy | Administrative & support | 2025 |
| Loikas agenturer Ab | Wholesale & retail | 2017 |
| Lombardi Advisory Ab | Professional & scientific | 2024 |
| Lotsberget Ab | Real estate | 2019 |
| Lu-Tec Ab | Manufacturing | 2019 |
| Lucky Smile Development Ab | Health & social care | 2025 |
| Lumenvik Ab | Real estate | 2023 |
| Lundbergs revisions- och konsultbyrå Ab | Professional & scientific | 1983 |
| Lundqvist Rederierna ab | Transport & logistics | 1968 |
| Lunmatic Ab | Wholesale & retail | 1990 |
| Lyyski Capital I Ab | Real estate | 2023 |
| Lyyski Holding Ab | Financial services | 2024 |
| Läderbiten på Åland Ab | Wholesale & retail | 1991 |
| Lönnroths snickeri AB | Construction | 2025 |
| MAR Trading Ab L Perander | Wholesale & retail | 1988 |
| Marilaw AB | Professional & scientific | 2012 |
| MB Redovisning Ab | Professional & scientific | 2023 |
| MBS Maritime Ab | Transport & logistics | 2018 |
| MECAX Consulting AB | Real estate | 2020 |
| MELI Holding Ab | Financial services | 2026 |
| MEQ Consulting Ab | Administrative & support | 2016 |
| MERIDIANA eko ab | Professional & scientific | 2007 |
| MGB Fastigheter Ab | Construction | 2016 |
| MH Disponent & Konsult AB | Real estate | 1988 |
| MH Marinteknik AB | Other services | 2018 |
| MHD Advokatbyrå Ab | Professional & scientific | 2008 |
| MI-Data Ab | Wholesale & retail | 1991 |
| Midax AB | Wholesale & retail | 2015 |
| MILELE TANZANIA SAFARIS & AGRITOURISM Ab | Administrative & support | 2025 |
| MJ Holmborg AB | Construction | 2021 |
| MKN-Invest Ab | Professional & scientific | 1992 |
| MN Måleri Ab | Construction | 2018 |
| MRH Entreprenad & Fastighets Ab | Construction | 1998 |
| MT Casino Ab | Arts & recreation | 1987 |
| MY-06 Ab | Construction | 2021 |
| MaSa Bygg AB | Construction | 2016 |
| Madeleine Sandell Ab | Professional & scientific | 2014 |
| Magazine Promotion Services Ab Oy | Wholesale & retail | 2010 |
| Magic Table Holding Ab | Professional & scientific | 2013 |
| Magictan Finland Ab | Wholesale & retail | 2004 |
| Maison Sandberg Ab | Wholesale & retail | 2026 |
| Majeng Ab | Real estate | 1986 |
| Maple Capital Oy | Financial services | 2026 |
| MarPo Ab | Professional & scientific | 2019 |
| Mariehamns Bioenergi Ab | Energy | 1994 |
| Mariehamns Bygg & betong Ab | Construction | 2018 |
| Mariehamns Centralantennaktiebolag | Information & communication | 1980 |
| Mariehamns Datahus AB | Wholesale & retail | 1979 |
| Mariehamns Dataprodukter Ab | Information & communication | 1983 |
| Mariehamns Elementbyggen Ab | Manufacturing | 2009 |
| Mariehamns Energi Ab | Energy | 2013 |
| Mariehamns Grönsaker Ab | Wholesale & retail | 1984 |
| Mariehamns Ingenjörskonsult Ab | Professional & scientific | 1981 |
| Mariehamns Kontorsmaskiner Ab | Wholesale & retail | 2006 |
| Mariehamns Motorcompany Ab | Wholesale & retail | 2002 |
| Mariehamns Motorcompany Holding Ab | Real estate | 1986 |
| Mariehamns Ord & Ton Ab | Information & communication | 1989 |
| Mariehamns Persondatorer Ab | Wholesale & retail | 1986 |
| Mariehamns Rederiaktiebolag | Transport & logistics | 1917 |