Pääjärvi may refer to:
Lakes Lake Pyaozero (Finnish: Pääjärvi), located in the Republic of Karelia, Russia Pääjärvi (Karstula), located in Karstula in the region of Keski-Suomi, Finland Pääjärvi (Lammi), located between the cities of Hämeenlinna and Hämeenkoski, Finland
Settlements Pyaozersky, a settlement in the Republic of Karelia, Russia, called Pääjärvi in Finnish
People Jörgen Pääjärvi (born 1969), Swedish freestyle skier Magnus Pääjärvi (born 1991), Swedish ice hockey player