Religious life in Finland since the Protesrant Reformation has been dominated by the Lutheran Church of Finland. For most of this period, almost all Finns belonged to it. In the late 1980s, about 90 percent of the population were members, and an even greater number participated in its rituals. During the time of Swedish rule, the church was the country's state church, and it was part of the national government, subordinate to the Swedish king. Even when headed during the nineteenth century by Russian tsars of the Orthodox faith, the Lutheran Church remained a state church. Since 1809, however, it has had to share this distinction with the Orthodox Church, which had followers in the eastern province of Karelia.

The Ecclesiastical Law of 1869 gave the Lutheran Church a measure of independence from the state by allowing it a representative body, the Synod, that could decide many important church matters on its own. When Finland became independent, the church gained a greater degree of autonomy, although it still was subject to state supervision. The president, for example, decided who was to become a bishop, using a list of three candidates submitted by the Lutheran Church. In 1943 the formation of its own central administration, separate from the Ministry of Education, meant the church was largely self-sufficient. Some practical matters, such as levels of church taxes, salaries and pensions, or reorganization of church districts, were still decided by the government or required its approval, but in many other matters the church set its own course.

A study commission of 1977 recommended a greater separation of church and state as a goal for Finnish society. The next decade's discussion of abolishing the presidential selection of bishops was one example of efforts to realize this goal. The gradual movement away from the national government meant that the Lutheran Church of Finland, although still a state church, was more independent than the other Lutheran churches of the Nordic region. This independence was so marked that students of religion commonly regarded it not so much as a state church, but as a folk church that served all Finns, members and nonmembers alike.

Data as of December 1988