| Hava Harju Oy | Arts & recreation | 2026 |
| HeViMet Oy | Manufacturing | 2014 |
| Heikkilän Rengas ja Varaosa Oy | Wholesale & retail | 1998 |
| Heirent Ky | Administrative & support | 2017 |
| Helmi Kuljetus Oy | Transport & logistics | 2008 |
| Helminen & Helminen | Wholesale & retail | 1986 |
| Hemiva Oy | Manufacturing | 2001 |
| Henkilöstöpalvelu Syrjälä Oy | Administrative & support | 2002 |
| Henkilöstöpalvelut Duuri-tiimi Oy | Administrative & support | 2019 |
| Herkko Holding Oy | Financial services | 1982 |
| Hessun Peltirakennus Ky, Heikki Järvinen | Construction | 1988 |
| Hevosklinikka Bela Arosalo Oy | Professional & scientific | 2011 |
| Hevossilta Oy | Hospitality | 1987 |
| Hinauspalvelu Vikman Oy | Other services | 1982 |
| HoivaSydän Oy | Health & social care | 2015 |
| Holdatum Oy | Financial services | 2023 |
| Hopeahelmi Hoivapalvelut Oy | Health & social care | 2021 |
| Horkan Kortti Oy | Wholesale & retail | 2022 |
| Hotelli Maakunta Forssa Oy | Hospitality | 2009 |
| House Team Europe Oy | Construction | 2015 |
| Hummala Wellness Oy | Other services | 2020 |
| Humppilan Lämpö Oy | Real estate | 1976 |
| Hushållska Oy | Wholesale & retail | 2015 |
| Hyvinvointi Mariette Ky | Other services | 2023 |
| Hämeen Arvokiinteistöt Oy | Real estate | 2023 |
| Hämeen Autonurkka Oy | Wholesale & retail | 2023 |
| Hämeen Autopalvelu Oy | Other services | 2021 |
| Hämeen Eristys ja Vesitekniikka Oy | Construction | 2012 |
| Hämeen Konttorityöpalvelu Oy | Professional & scientific | 1983 |
| Hämeen Kuivaustekniikka Oy | Construction | 2007 |
| Hämeen LVI Konsultointi Oy | Construction | 1997 |
| Hämeen Painehuolto Oy | Construction | 2001 |
| Hämeen Paino Oy | Manufacturing | 2004 |
| Hämeen Panttilainakonttori Oy | Financial services | 1992 |
| Hämeen Putkityö Oy | Construction | 2005 |
| Hämeen Sijoituspalvelut Ky | Financial services | 2007 |
| Hämeen Taitolaskenta Ky | Professional & scientific | 2016 |
| Hämeen Tilitieto Oy | Professional & scientific | 2024 |
| Hämeen Valtatieravintolat Oy | Hospitality | 1993 |
| Hämeentien Autoburger Oy | Hospitality | 2024 |
| Härkäpuu Oy | Construction | 1989 |
| ILKM Oy | Hospitality | 2020 |
| IT-Partners Oy Ltd | Information & communication | 2017 |
| Ideal Automation Oy | Professional & scientific | 2011 |
| Ihonhoito Glow Oy | Other services | 2022 |
| Ilon lähde Oy | Wholesale & retail | 1999 |
| Infra Vinnikainen Oy | Construction | 2020 |
| InsTsto Elecplan Oy | Professional & scientific | 2022 |
| Insinööritalo Malliva Oy | Professional & scientific | 2006 |
| Insinööritoimisto Macel Oy | Professional & scientific | 1985 |
| Ivaso Oy | Construction | 1991 |
| J & J - kiinteistöt Oy | Real estate | 2006 |
| J & J Vainio Oy | Administrative & support | 2019 |
| J & P Kantelus Oy | Transport & logistics | 2006 |
| J. Alku-Suunnittelu Oy | Professional & scientific | 1992 |
| J. O-Bike Oy | Other services | 1996 |
| JAC-Food Oy | Hospitality | 2020 |
| JE-Rengas Oy | Wholesale & retail | 2013 |
| JJS-Sijoitus Oy | Financial services | 2011 |
| JJS-Trading Oy | Wholesale & retail | 2025 |
| JK Silmäasemat Oy | Financial services | 1989 |
| JP mittaus- ja valvontapalvelut Ky | Construction | 2018 |
| JR Company Oy | Information & communication | 2026 |
| JS Properties Oy | Real estate | 2024 |
| JT Tulander Oy | Professional & scientific | 2026 |
| JTN-Asennus Oy | Construction | 2006 |
| JURO SÄHKÖAJONEUVOT Oy | Wholesale & retail | 2019 |
| Jaana Lindfors Ky | Wholesale & retail | 1983 |
| Jalorauta Oy | Manufacturing | 2021 |
| Janvas Oy | Wholesale & retail | 2014 |
| Jarin Vene, Kone ja Työ Ky | Other services | 2005 |
| Jarobo Solutions Oy | Manufacturing | 2015 |
| Jaskan Huoltopiste Oy | Other services | 1988 |
| Jauhiainen & Fonsén Oy | Construction | 2012 |
| Jennin Auto Oy | Professional & scientific | 1989 |
| JoJ-Apu Oy | Construction | 2025 |
| Joecon Oy | Professional & scientific | 1992 |
| Johki Oy | Arts & recreation | 2009 |
| Jokioisten Maanrakennus Oy | Construction | 1997 |
| Jokioisten Säästövinkki Oy | Wholesale & retail | 1993 |
| Jokioisten Tennis Oy | Arts & recreation | 1991 |
| Jokkis-Keittiöt Oy | Manufacturing | 1988 |
| Jokkis-Laiturit Avoin yhtiö | Construction | 1991 |
| Jolie Ravintolat Oy | Hospitality | 2026 |
| Jomeks Oy | Manufacturing | 1986 |
| Jomet Oy | Manufacturing | 1977 |
| Jorma Hakalan Kiinteistöt Oy | Real estate | 1988 |
| Jorp Oy | Construction | 2023 |
| Jospak Oy | Manufacturing | 2014 |
| Joyride Games Oy | Manufacturing | 2004 |
| Jude Iida Oy | Arts & recreation | 2026 |
| Jukka Kaleva Oy | Financial services | 1994 |
| Juro Sharing Infra Oy | Other services | 2019 |
| Järvenpää Oy | Manufacturing | 1985 |
| K&M Virtanen Oy | Financial services | 2023 |
| KASTIA-Palvelut Oy | Other services | 2022 |
| KG-Kuljetus Oy | Transport & logistics | 1995 |
| KHJ-Invest Oy | Hospitality | 2017 |
| KJ Kuutiot Oy | Construction | 2022 |
| KJR-Asennus Oy | Construction | 2016 |