| Osuuskunta Senioriekspertit - Senior Experts | Administrative & support | 1997 |
| Ottobre Oy | Wholesale & retail | 1997 |
| Oulun Kaukokiito Oy | Transport & logistics | 1960 |
| Ounas Partners Oy | Professional & scientific | 2015 |
| Ounas-Kuukkeli Ky | Hospitality | 1988 |
| OunasHelisten Avoin yhtiö | Real estate | 2011 |
| OunasIsännöinti Oy | Real estate | 2025 |
| Ounasrakenne Oy | Construction | 1990 |
| Ounasremontti Oy | Construction | 2011 |
| Ounasruuvi Ky | Wholesale & retail | 1992 |
| Ounastus Oy | Professional & scientific | 2025 |
| Ounasvaaran Areena-Palvelut Oy | Hospitality | 2005 |
| Ounasvaaran Hiihtokeskus Oy | Arts & recreation | 2005 |
| Outa Creative Oy | Professional & scientific | 2021 |
| OutdO2r Xperiences Oy | Administrative & support | 2022 |
| Outza Holding OY | Real estate | 2024 |
| Overpower Oy | Manufacturing | 2019 |
| Oy Arctic Motorcycles Ltd | Real estate | 2001 |
| Oy Arctic Show Store Ltd | Professional & scientific | 2008 |
| Oy Arctic Staff Service Ltd | Administrative & support | 2015 |
| Oy Con-Frakt Ab | Transport & logistics | 2006 |
| Oy Distripoint Ltd | Transport & logistics | 2002 |
| Oy Inarin Hietavilla | Real estate | 1985 |
| Oy Karaokekeskus Trading Finland Ltd | Wholesale & retail | 2004 |
| Oy Lapland Legacy Ltd | Administrative & support | 2025 |
| Oy Lomara Ab | Real estate | 1989 |
| Oy Sevennet Ltd | Information & communication | 1998 |
| Oy TH-International Ltd | Financial services | 1996 |
| Oy White & Green Chalets Ltd | Hospitality | 2007 |
| Oy Zawar Resources Finland Ltd | Mining & quarrying | 2016 |
| P&M Speakers avoin yhtiö | Wholesale & retail | 2012 |
| PE-Center Oy | Education | 2016 |
| PF Talous Oy | Professional & scientific | 2019 |
| PGF Autokorjaamo Oy | Other services | 2020 |
| PHK-Konsultointi Oy | Wholesale & retail | 2002 |
| PIBO Creative Oy | Professional & scientific | 2013 |
| Pintamaster OY | Construction | 2015 |
| PK Kauneus Oy | Other services | 2026 |
| PKV Group Oy | Wholesale & retail | 2007 |
| PL-Kone Ky | Construction | 2002 |
| PM-Taso Oy | Construction | 1995 |
| PMH Capital Oy | Professional & scientific | 2026 |
| Poweria OY | Professional & scientific | 2009 |
| PR Diesel ja Autosähkö kommandiittiyhtiö | Other services | 1986 |
| PT-Auto Oy | Wholesale & retail | 1983 |
| PT-Talotekniikka Oy | Real estate | 2017 |
| Paavalniemen Konditoria & Catering Oy | Wholesale & retail | 2019 |
| Pabo Oy | Financial services | 2022 |
| Padel Hombres Oy | Wholesale & retail | 2022 |
| Padel Oy Rovaniemi | Arts & recreation | 2025 |
| Pakettikuljetus Uutela Ky | Transport & logistics | 2025 |
| Palis Ky | Wholesale & retail | 1966 |
| Pallari Consulting Oy | Information & communication | 2023 |
| Pallas Rakennus Lappi Oy | Construction | 2016 |
| Palosalmi Oy | Wholesale & retail | 2024 |
| Palotta Lappi Oy | Wholesale & retail | 2026 |
| Palvelukeskus Koivu Team Oy | Administrative & support | 2021 |
| Palvelut Juuso Ky | Real estate | 1999 |
| Palvelutaksi Reijo Huttunen Ky | Transport & logistics | 1992 |
| Panna Enterprises Oy | Education | 2026 |
| Pappaboy Oy | Manufacturing | 1997 |
| Parasol Medical Oy | Health & social care | 2024 |
| Pasula Petteri Ky | Professional & scientific | 2012 |
| Patomajat, Haavikko & Kni Kommandiittiyhtiö | Wholesale & retail | 1979 |
| Pauli Juujärvi Oy | Transport & logistics | 1981 |
| Pauliina Mulari Oy | Other services | 2020 |
| Pee Kolmanteen Oy | Hospitality | 2023 |
| Peja Arctic Oy | Administrative & support | 2019 |
| Pekka Haarala Oy | Other services | 2023 |
| Pekka Ruotsala Ky | | 1986 |
| Pellon Palvelukoti Tarja Rahtu Ky | Health & social care | 1996 |
| Perhekoti Kaje Oy | Health & social care | 2020 |
| Peräpohjolan Laki- ja Rakennuskonsultointi Oy | Professional & scientific | 1989 |
| Pestatilit Oy | Professional & scientific | 2007 |
| Pesulappi Oy | Other services | 2024 |
| Petteri Pellikka Oy | Transport & logistics | 1996 |
| Pevest Oy | Financial services | 1986 |
| Phoenix Palvelut Oy | Transport & logistics | 2026 |
| Phoenix Point Oy | Information & communication | 2020 |
| Pick nDdrop Rova OY | Wholesale & retail | 2021 |
| Pienkone Karvo OY | Wholesale & retail | 2015 |
| Piesku Oy | Wholesale & retail | 2004 |
| Piharakennus Linden Oy | Construction | 2024 |
| Piiseven Oy | Professional & scientific | 2025 |
| Piisi-Maijanen Oy | Real estate | 2008 |
| Piisipojat Oy | Real estate | 1990 |
| Pikasuutari Paikka Oy | Other services | 2004 |
| Piketti-Ravintola Ky | Hospitality | 1989 |
| PineLake Oy | Professional & scientific | 2017 |
| Pink Phoenix Oy | Wholesale & retail | 2024 |
| Pinta Puu Oy | Construction | 1993 |
| Piriko Oy | Hospitality | 2008 |
| Pisteraja kiinteistöt Oy | Real estate | 2013 |
| Pizza&kebab huoes oy | Hospitality | 2022 |
| Pizza&kebab venninpiste oy | Hospitality | 2022 |
| Pizzeria Magenta Oy | Hospitality | 2021 |
| Pohjois-Suomen Betonilattiat Oy | Construction | 2024 |
| Pohjois-Suomen Energiatieto Oy | Information & communication | 2007 |
| Pohjois-Suomen LVI Oy | Construction | 2017 |
| Pohjois-Suomen Löytötavarapalvelu Oy | Administrative & support | 2012 |