| King Services Oy | Administrative & support | 2021 |
| Kino Kirkkonummi Oy | Information & communication | 2016 |
| Kipinä Valmennus Oy | Education | 2015 |
| KirKe-halli Oy | Real estate | 2002 |
| Kirkkonummen Autofiksi Oy | Other services | 2016 |
| Kirkkonummen Autopalvelu Oy | Other services | 2019 |
| Kirkkonummen Biili Oy | Wholesale & retail | 2021 |
| Kirkkonummen Erävaruste Oy | Wholesale & retail | 1994 |
| Kirkkonummen Huolto Oy | Administrative & support | 1974 |
| Kirkkonummen Komerot Oy | Transport & logistics | 2008 |
| Kirkkonummen Kukka ja Hautauspalvelu Oy | Wholesale & retail | 2003 |
| Kirkkonummen Kunnossapito ja Rakennus Oy | Construction | 1998 |
| Kirkkonummen Mehiläistarhat Ky | Wholesale & retail | 2002 |
| Kirkkonummen Mehiläistuote Oy | Wholesale & retail | 2016 |
| Kirkkonummen Monitoimihalli Oy | Real estate | 2000 |
| Kirkkonummen Optiikka Ky | Wholesale & retail | 1986 |
| Kirkkonummen Rengas Ojala OY | Wholesale & retail | 2020 |
| Kirkkonummen Sanomat Oy | Information & communication | 1982 |
| Kirkkonummen Tennishalli Oy | Arts & recreation | 2026 |
| Kirkkonummen Urheilu ja Vapaa-aika Ky | Wholesale & retail | 1983 |
| Kirkkonummen Urheilukentät Oy | Arts & recreation | 2021 |
| Kirkkonummen Vuokra-asunnot Oy | Real estate | 1994 |
| Kirkkonummen kunto-ja valmennuskeskus NiNoRi Oy | Arts & recreation | 1984 |
| Kirtili Oy | Professional & scientific | 1985 |
| Kitaraverstas Lassi Nurmi Oy | Manufacturing | 1995 |
| Kiviniilo Oy | Manufacturing | 2024 |
| Kivistön Parkki Oy | Real estate | 2022 |
| Koiran mieli Oy | Arts & recreation | 2016 |
| Koiratarvike Haukkula Oy | Wholesale & retail | 2024 |
| Kommanditbolag Frigoterm Ky | Manufacturing | 1983 |
| Koneoperaattorit Oy | Transport & logistics | 2011 |
| Konsultointi Parvinen Oy | Financial services | 2005 |
| Konsulttitoimisto Synteesi Oy | Professional & scientific | 1988 |
| Korter Finland Oy | Construction | 2009 |
| Kosa Oy | Professional & scientific | 2005 |
| Kotikulman Helmi Oy | Construction | 2024 |
| Kotipalvelu Wallenius Oy | Administrative & support | 2016 |
| Kotipiste B&F Oy | Real estate | 1994 |
| Koto Holding Oy | Real estate | 2026 |
| Kraftig Management Oy | Financial services | 2016 |
| Kuljetusliike Narvanne & Kumpp. | Transport & logistics | 1961 |
| Kustannusosakeyhtiö Kuvio Oy | Information & communication | 2019 |
| Ky Gräsbeck International Kb | Arts & recreation | 1994 |
| Kylander Consulting Oy | Professional & scientific | 2018 |
| Kylander Invest Ab | Financial services | 2023 |
| Kyläkoski Oy | Professional & scientific | 2020 |
| Kyrkslätt JH-Fastighetsservice Ab | Administrative & support | 1996 |
| Kyrkslätts Begravningstjänst Bo R Lindström Ab | Other services | 1996 |
| LDFIN Oy | Wholesale & retail | 2024 |
| Luli Palvelut OY | Hospitality | 2008 |
| LUXEL Sähköpalvelut Oy | Construction | 2017 |
| LVISELVIS 24 Oy | Construction | 2015 |
| Laburnum Oy Ab | Financial services | 1997 |
| Lakisa Oy | Construction | 2021 |
| Larsen bygg Oy | Construction | 2005 |
| Lean Demeter Oy | Professional & scientific | 2022 |
| LearnForward Oy | Education | 2026 |
| Leikki & Ilo Oy | Arts & recreation | 2026 |
| Leissox Avoin yhtiö | Professional & scientific | 2011 |
| Lemixet Oy | Professional & scientific | 2021 |
| Lentoon Oy | Professional & scientific | 2021 |
| Leo Bass Oy | Administrative & support | 2011 |
| Les Iles Oy | Financial services | 2012 |
| Lille & Roininen Food Services Oy | Hospitality | 2019 |
| LindbergCoaching Oy | Education | 2024 |
| Lindman & Co Oy | Financial services | 2012 |
| Liquid & Sport Consulting Finland Oy | Professional & scientific | 2015 |
| Lisaiv Oy | Construction | 2016 |
| Listo Digital Oy | Professional & scientific | 2020 |
| Livilia Oy | Professional & scientific | 2022 |
| Ljungqvist Capital Oy | Manufacturing | 2019 |
| Lofizen Oy | Information & communication | 2024 |
| Logislet Partners Oy | Professional & scientific | 2021 |
| Loistava Mainos Oy | Professional & scientific | 2019 |
| Lomavi Oy | Financial services | 2025 |
| Longshot Invest Oy | Financial services | 2026 |
| Loop and Line Oy | Professional & scientific | 2016 |
| Louhea Oy | Professional & scientific | 2020 |
| Louhicare Oy | Wholesale & retail | 2026 |
| Ltd Sartorius Oy | Education | 1995 |
| LuckyStars Oy | Financial services | 2020 |
| Luigi Oy | Transport & logistics | 2022 |
| Lumu Oy | Information & communication | 2024 |
| Lunacap Oy | Construction | 1996 |
| Lune Oy | Administrative & support | 2022 |
| Luoman Ravintolat Oy | Hospitality | 1999 |
| Luottolääkäri Oy | Health & social care | 2025 |
| Luottotaksi Oy | Transport & logistics | 2025 |
| Lähipalvelut Suomi Oy | Information & communication | 2014 |
| Lämpökaverin ruiskutuspalvelut Oy | Construction | 2019 |
| Länsi-uudenmaan saaristopalvelut Oy | Construction | 2000 |
| Länsiväylän Konepalvelu Oy | Construction | 1989 |
| M.Helminen Oy | Construction | 2021 |
| M3 Konsultit Oy | Professional & scientific | 2013 |
| MA Consulting Oy | Administrative & support | 2020 |
| Mariprinsessa OY | Other services | 2024 |
| Miheli OY | Construction | 2016 |
| MJ Accounting Oy | Professional & scientific | 2019 |
| MJH-Safety Oy | Education | 2024 |
| MJT Capital Oy | Real estate | 2021 |