Eastern Orthodox church, recognized as the second state church of Finland. Most of the Orthodox Finns were originally from Karelia, the southeastern part of Finland that was annexed by the Soviet Union in 1940, which was Christianized by Russian monks in the 12th century. The Orthodox are now spread throughout Finland. The church has two dioceses, Kuopio and Helsinki, and a seminary. Having separated itself from Russian jurisdiction when Finland became an independent republic after World War I, it was granted autonomy (independence except in relations with other churches and in the appointment of its archbishop) in 1919 by the patriarch of Moscow but then transferred to the jurisdiction of Constantinople with autonomous status in 1923.

The Finnish Orthodox Church numbers about 60,000 faithful, a little over 1 percent of the total population in a predominantly Lutheran country. It follows the Western dates for Easter and the fixed feasts and uses Finnish and Slavonic as liturgical languages. There are three Orthodox monasteries, an archbishop at Kuopio, and a bishop at Helsinki.