| Henku Oy | Financial services | 2019 |
| Henten Perinne Savukala Oy | Manufacturing | 2013 |
| Hepolahden Saarnola Oy | Real estate | 1988 |
| Herkkuperhe Oy | Hospitality | 2012 |
| Herkkä Snacks Oy | Wholesale & retail | 2021 |
| Herttoniemen Kylmätekniikka Oy | Construction | 2024 |
| Herttuan Kiinteistöpalvelu Oy | Real estate | 2012 |
| Hervannan Kuriiri Oy | Transport & logistics | 2002 |
| Hestia Holdings OY | Real estate | 2026 |
| Hevoshaan Maa ja Maisema Osk | Administrative & support | 2002 |
| Hevosport Oy | Wholesale & retail | 2025 |
| Hevosvoima Oy | Education | 2009 |
| Hienopuusepäntyö Elmwood Ky | Construction | 2006 |
| Hiltzun Grilli-Ravintola Ky | Hospitality | 1986 |
| Hinausautot Raimo Moisio Oy | Transport & logistics | 2008 |
| Hiprotec Oy | Administrative & support | 2012 |
| Hirvelän Kaurapaahtimo Oy | Manufacturing | 2023 |
| Hitmate Junior Ltd Oy | Manufacturing | 2023 |
| Hitsausapulaite Oy | Manufacturing | 1975 |
| Hiusmesta Oy - Monika Törmälä | Other services | 2023 |
| Hoito- ja hoivapalvelu sair.hoit. Taru Koskivuori Oy | Health & social care | 2016 |
| Hoivapalvelu Auttavaiset Oy | Health & social care | 2019 |
| Holiday Moto-Rent Oy | Wholesale & retail | 2019 |
| Hollon Voima Ky | Professional & scientific | 2006 |
| Holodeck Industries Oy | Information & communication | 1994 |
| Homehill Oy | Administrative & support | 2004 |
| Hongas Oy | Real estate | 2011 |
| Honkasen Puutarha Oy | Wholesale & retail | 1987 |
| Hujanhajan Oy | Administrative & support | 2023 |
| Hunajana Oy | Information & communication | 2020 |
| Hurlum Invest Oy | Financial services | 2022 |
| Huvikummun Hevostalli Avoin yhtiö | Agriculture & fishing | 2010 |
| Hyyra Oy | Information & communication | 2020 |
| Hämeen Kivipinta Oy | Construction | 2025 |
| Hämeen Malli ja Muotti Oy | Wholesale & retail | 1985 |
| Hämeen Radiologia Oy | Health & social care | 2019 |
| Hämeen Rakennuspelti Oy | Construction | 2026 |
| I & Y Team Oy | Transport & logistics | 2023 |
| IKASET Oy | Manufacturing | 2017 |
| IM Works Oy | Construction | 2020 |
| Interactive Digital Media OY Indime | Information & communication | 2000 |
| IR Creative Design Oy | Financial services | 2022 |
| Icona Oy | Real estate | 2018 |
| Ideal Construction Oy | Construction | 2003 |
| Ifelse Media Oy | Information & communication | 2011 |
| Ikirauta Oy | Manufacturing | 2000 |
| Ilkon Kukka Oy | Wholesale & retail | 1984 |
| Ilkon Tili ja Tempaus Oy | Professional & scientific | 2024 |
| Ilkonhovi Oy | Real estate | 2009 |
| Inets Vision Oy | Wholesale & retail | 2021 |
| Inferno Kapital Oy | Professional & scientific | 2004 |
| Infraset Oy | Professional & scientific | 2013 |
| Inhaber Oy | Financial services | 2005 |
| InnoFors Oy | Professional & scientific | 1991 |
| Insinööri- ja Rakennuspalvelu Parain Oy | Construction | 2019 |
| Insinööritoimisto EnergiaTalo Oy | Real estate | 2012 |
| Insinööritoimisto Energiainssit Oy | Professional & scientific | 2013 |
| Insinööritoimisto Erik Hakkarainen Oy | Construction | 2014 |
| Insinööritoimisto Jarkko Jokinen Oy | Professional & scientific | 1996 |
| Insinööritoimisto K.J. Saarinen Oy | Manufacturing | 1989 |
| Insinööritoimisto Suoranta Oy | Professional & scientific | 2017 |
| Instpro Automation Ky | Professional & scientific | 2002 |
| Into Accounting Oy | Professional & scientific | 2009 |
| Invea Oy | Real estate | 2003 |
| Iris Invest Oy | Financial services | 2009 |
| IronFamily Oy | Education | 2021 |
| Isoaho Computing Ky | Information & communication | 1953 |
| Isännöinti Piikkilä Oy | Real estate | 2015 |
| Isännöinti Susu Tossavainen Oy | Real estate | 2019 |
| Isännöintitalo Muranen Oy | Real estate | 2017 |
| Itkuton Oy | Health & social care | 2021 |
| Ivars Group Oy | Financial services | 2025 |
| J & H Laatoitus Oy | Construction | 2015 |
| J 3 Medical Oy | Health & social care | 2000 |
| J. Aro Ky | Construction | 1990 |
| JEP Tarkastus Oy | Professional & scientific | 2024 |
| JHSH-tuotanto Oy | Manufacturing | 1982 |
| JJ Putkitus Oy | Construction | 2015 |
| JJ-Autokeskus Oy | Wholesale & retail | 2022 |
| JJ-Electric Oy | Financial services | 2025 |
| JJK-Data Ky Jari Kulmala | Information & communication | 1991 |
| JJV Machine Afääri Oy | Agriculture & fishing | 1996 |
| JK Supplement Oy | Wholesale & retail | 2025 |
| JLA Holding Oy | Professional & scientific | 2012 |
| JMR Consulting Oy | Professional & scientific | 2025 |
| JMS Sound Oy | Administrative & support | 1995 |
| JO Motor Ky | Wholesale & retail | 2009 |
| JPR Consulting Oy | Professional & scientific | 2022 |
| JPond Oy | Professional & scientific | 2011 |
| JR Motor Group Oy | Wholesale & retail | 2010 |
| JT Innovation Oy | Manufacturing | 2022 |
| JTP Business Innovations Oy | Professional & scientific | 2011 |
| JW-Rakennustyö Oy | Construction | 2014 |
| Ja Rakennus ja Saneeraus Oy | Construction | 2021 |
| JaTiPack Oy | Wholesale & retail | 2023 |
| Jackpot Films Oy | Information & communication | 1998 |
| Jakahet Oy | Professional & scientific | 1988 |
| Jakestania Oy | Real estate | 2001 |
| JakoRasia Oy | Transport & logistics | 2007 |
| Jaloterät Oy | Manufacturing | 2005 |