The Greek Orthodox Church is the doctrine that represents the majority of the population in the country and is recognized constitutionally as the "prevailing religion" of the state. Other major religions in Greece are Catholicism, Islam and Protestantism.
The Constitution of Greece in SECTION II: Relations between Church and State, Article 3 states:
The prevailing religion in Greece is that of the Eastern Orthodox Church of Christ. The Orthodox Church of Greece, acknowledging our Lord Jesus Christ as its head, is inseparably united in doctrine with the Great Church of Christ in Constantinople and with every other Church of Christ of the same doctrine. It observes unwaveringly, as they do, the holy apostolic and synodical canons and sacred traditions. It is autocephalous and is administered by the Holy Synod of serving Bishops and the Permanent Holy Synod originating thereof and assembled as specified by the Statutory Charter of the Church in compliance with the provisions of the Patriarchal Tome of June 29, 1850 and the Synodal Act of September 4, 1928.