Pääjärvi may refer to:

Lakes

* Pääjärvi (Karstula), located in Karstula in the region of Keski-Suomi, Finland * Pääjärvi (Lammi), located between the cities of Hämeenlinna and Hämeenkoski, Finland * Lake Pyaozero (Finnish: Pääjärvi), located in the Republic of Karelia, Russia

Settlements

* Pyaozersky, a settlement in the Republic of Karelia, Russia, called ''Pääjärvi'' in Finnish

People

* Magnus Pääjärvi (born 1991), Swedish ice hockey player {{disambig, geo, surname