| Orimek Ky | Wholesale & retail | 1987 |
| Oriweld Oy | Construction | 2021 |
| Ormeko Oy | Agriculture & fishing | 1997 |
| Ortek Invest Oy | Real estate | 2021 |
| Ortek Oy | Construction | 2021 |
| Osakeyhtiö Yhtyneet Työväenjärjestöt | Real estate | 1947 |
| Osasto Nurmikari OY | Administrative & support | 2019 |
| Oy 812 Group | Construction | 1992 |
| Oy BBW BelieweBlackWind | Administrative & support | 1988 |
| Oy BZM Scan-palvelut Ab Ltd | Wholesale & retail | 1996 |
| Oy BZM W-Company Ab Ltd | Construction | 1996 |
| Oy IBG Inutil Box Group Ab Ltd | Construction | 1996 |
| Oy JSZ-Group Ltd | Wholesale & retail | 1996 |
| Oy Teejii-Tuloste | Professional & scientific | 1991 |
| Oy Unbeatable Ab | Wholesale & retail | 2007 |
| P-H Putkimiespalvelut Oy | Construction | 2012 |
| P. Konua & Co. Oy | Wholesale & retail | 2017 |
| Paa OY | Hospitality | 2024 |
| Paljuässät OY | Administrative & support | 2015 |
| PJJ-Palvelut Oy | Wholesale & retail | 2007 |
| PROnx-yhtiöt Oy | Construction | 1997 |
| Paco Group Oy | Professional & scientific | 2026 |
| PadelMesta Oy | Arts & recreation | 2021 |
| Pallet Master Oy | Manufacturing | 2023 |
| Palojoen Kuljetus Ky | Transport & logistics | 1989 |
| Palonahon perhekoti Oy | Health & social care | 2006 |
| Pangolin Oy | Manufacturing | 2025 |
| Parts Osa Oy | Wholesale & retail | 2025 |
| Parturi Corneri Oy | Other services | 2022 |
| Parveke- ja terassilasihuolto MH Oy | Construction | 2018 |
| Pecten Oy | Financial services | 1993 |
| PeeJii Oy | Real estate | 1990 |
| Pekkalan Korjaamo Oy | Other services | 1987 |
| Pelti-Kaikko Oy | Construction | 2015 |
| Peltisepänliike Sahervo Oy | Construction | 2006 |
| Pentti Järvi Ky | Other services | 1992 |
| Perhekotiyhteisö Oljenkorsi Oy | Health & social care | 2011 |
| Perseverans Oy | Mining & quarrying | 2026 |
| Personal tili Ky | Professional & scientific | 2016 |
| Perttola Sijoitus Oy | Financial services | 2007 |
| Petokuljetus Oy | Transport & logistics | 2016 |
| Piikainkyrön Vesiosuuskunta | Water & waste | 2007 |
| Pitsi & Palmikko Ky | Wholesale & retail | 2012 |
| Pitäjäsanomat Oy | Information & communication | 1952 |
| Planemill Finland Ltd Oy | Manufacturing | 2005 |
| Pohjolan Mk-lattiatyö Oy | Construction | 2000 |
| Polar Industria Oy | Professional & scientific | 2026 |
| Posicraft Oy | Wholesale & retail | 1993 |
| Powersteam Oy | Manufacturing | 2008 |
| Premium Audio osk | Information & communication | 2014 |
| Primesys Oy | Information & communication | 1999 |
| Pro Street Ky | Other services | 2015 |
| ProKolmio Oy | Construction | 2024 |
| Puu&Urakointi Oy | Administrative & support | 2021 |
| Puu- ja Pakkaustyö Reijonen Oy | Manufacturing | 1991 |
| Puu- ja kalustetuote, veljekset Ovaska Oy | Manufacturing | 1984 |
| Pwolle Group Oy | Wholesale & retail | 2025 |
| Päijät-Hämeen Kiinteistö Ja Huoltopalvelu OY | Construction | 2016 |
| Päijät-Hämeen Kiinteistösijoitus Oy | Real estate | 2015 |
| Päijät-Yhtiöt Oy | Construction | 2018 |
| Päivi Suutari Oy | Professional & scientific | 2016 |
| Päiväkoti Keinuhevonen Oy | Education | 2005 |
| Päiväkoti Orimattilan Elopelto Oy | Education | 2012 |
| Pölyn Poraus Piekäinen Oy | Administrative & support | 2016 |
| Pöyhtäri Design Oy | Wholesale & retail | 1999 |
| Quura Oy | Information & communication | 2017 |
| RM Romumetalli Oy | Wholesale & retail | 2003 |
| RP-Koneistusmiehet Oy | Manufacturing | 1989 |
| Rakennus Capital Oy | Real estate | 1990 |
| Rakennus Joukahainen Oy | Construction | 2010 |
| Rakennus N. Keskinen Oy | Construction | 2018 |
| Rakennus Nyholm Oy | Construction | 2022 |
| Rakennus Oy Pronssitie | Real estate | 1987 |
| Rakennus PALJE Oy | Construction | 2018 |
| Rakennus ja Arkkitehtuuri Heinonen Oy | Construction | 2022 |
| Rakennusliike Ari Ilola Oy | Construction | 2012 |
| Rakennusliike Häikiö & Rosenberg Oy | Construction | 2007 |
| Rakennuspalvelu Pekkinen Ky | Construction | 2001 |
| Rakennuspalvelu Sippola Oy | Construction | 2025 |
| Rakennuspalvelu Vepsäläinen Oy | Construction | 1994 |
| Rakennussora-Tumppi Ky | Mining & quarrying | 1987 |
| Rakennustoimisto HTM Oy | Construction | 2005 |
| Raksakaiffarit Oy | Construction | 2020 |
| Ralstar Oy | Financial services | 2020 |
| Rantasen Nahkajalostamo Oy | Manufacturing | 1962 |
| Rasavi Oy | Professional & scientific | 2015 |
| Ratema Oy | Real estate | 2005 |
| Ravintola Violetta Oy | Hospitality | 2018 |
| Ravipalvelu Jyrki Tammimetsä Ky | Arts & recreation | 1995 |
| Ravitalli Korvenheimo Oy | Arts & recreation | 2011 |
| Ravitalli Tapio Perttunen Ky | Arts & recreation | 1988 |
| Ravitalli Tikkala Ky | Arts & recreation | 1998 |
| Remontti Otti Oy | Construction | 2026 |
| RiheFix Oy | Construction | 2022 |
| Rinne Racing Ky | Arts & recreation | 1984 |
| Ripped Generation Oy | Wholesale & retail | 2017 |
| Ryhis Oy | Real estate | 2025 |
| SK-Hallit Oy | Real estate | 2005 |
| Sairaankuljetus M. Lipponen Ky | Health & social care | 1981 |
| Sakoni Oy | Professional & scientific | 2003 |