Catholic Church

Christianity in Cyprus is the largest religion in the country, making up 78% of the island's population. The largest Christian denomination is the Greek Orthodox Church, while the rest are smaller communities of Anglicans, Roman Catholics, Latin Christians, Maronites, Armenian Apostolics, and Greek Evangelicals.

Christianity in Russia is the most widely professed religion in the country. The largest tradition is the Russian Orthodox Church. According to official sources, there are 170 eparchies of the Russian Orthodox Church, 145 of which are grouped in metropolitanates. There are from 500,000 to one million Old Believers, who represent an older form of Russian Orthodox Christianity, and who separated from the Orthodox Church in the 17th century as a protest against Patriarch Nikon's church reforms.

The Catholic Church estimates that there are from 600,000 to 1.5 million Catholics in the country, exceeding government estimates of about 140,000. There is one Catholic Archdiocese, Mother of God at Moscow, with three suffragan dioceses (Saint Clement at Saratov, Saint Joseph at Irkutsk, Transfiguration at Novosibirsk) and the Apostolic Prefecture of Yuzhno-Sakhalinsk. According to the Slavic Center for Law and Justice, Protestants make up the second or third largest group of Christians in Russia, with approximately 3,500 organizations and more than 1 million followers. A large number of missionaries operating in the country are from Protestant denominations.

The Catholic branch of Christianity is the most widely professed religion in Spain, with high levels of secularization as of 2025. Freedom of religion is guaranteed by the Spanish Constitution.

Most people in Belgium do not belong to a religion. Christianity is the largest religion, with the Catholic Church representing the largest community, though it has experienced a significant decline since the 1950s (when it was the nominal religion of over 80% of the population). Belgium's policy separates the state from the churches, and freedom of religion is guaranteed by the country's constitution.

Christianity is the largest religion in the United Kingdom. Results of the 2021 Census for England and Wales showed that Christianity is the largest religion (though it makes up less than half of the population at 46.2%), followed by the non-religious (37.2%), Islam (6.5%), Hinduism (1.7%), Sikhism (0.9%), Buddhism (0.5%), Judaism (0.5%), and others (0.6%). Among Christians, Anglicanism is the most common denomination, with 53% of Christian believers in the UK identifying with this denomination as of 2023, followed by Catholicism, Presbyterianism, Methodism, Unitarianism, and Baptists. Results for the 2022 census in Scotland indicated that the majority (51%) had no religion, but that 38.8% of the Scottish population identified as Christian (of which 20% identified with the Church of Scotland and 13% with the Catholic Church). In Northern Ireland, Christianity is the largest religion (79.7%) followed by non-religious (17.4%), other religions (1.3%), and not stated (1.5%), as of 2021.

Christianity is the largest religion in Germany. It was introduced to the area of modern Germany by 300 AD, while parts of that area belonged to the Roman Empire, and later, when Franks and other Germanic tribes converted to Christianity from the fifth century onwards. The area became fully Christianized by the time of Charlemagne in the eighth and ninth century. After the Reformation started by Martin Luther in the early 16th century, many people left the Catholic Church and became Protestant, mainly Lutheran and Reformed. In the 17th and 18th centuries, German cities also became hubs of heretical and sometimes anti-religious freethinking, challenging the influence of religion and contributing to the spread of secular thinking about morality across Germany and Europe.

The most widely professed religion in Bosnia and Herzegovina is Islam and the second biggest religion is Christianity. Nearly all the Muslims of Bosnia are followers of the Sunni denomination of Islam; the majority of Sunnis follow the Hanafi legal school of thought (fiqh) and Maturidi theological school of thought (kalām). Bosniaks are generally associated with Islam, Croats of Bosnia and Herzegovina with the Catholic Church, and Bosnian Serbs with the Serbian Orthodox Church. The State Constitution of Bosnia and Herzegovina (BiH) and the entity Constitutions of the Federation of Bosnia and Herzegovina and the Republika Srpska provide for freedom of religion, and the Government generally respects this right in ethnically integrated areas or in areas where government officials are of the majority religion; the state-level Law on Religious Freedom also provides comprehensive rights to religious communities. However, local authorities sometimes restricted the right to worship of adherents of religious groups in areas where such persons are in the minority.

Government protection of religious freedom declined, especially during the campaign period prior to the October 2006 national elections, due to selective legal enforcement and the indifference of some government officials. At the end of the period covered by this report, the Government was implementing the State Law on Religious Freedom to protect the rights of religious communities and create a government registry allowing them to establish legal status.

In the Czech Republic, 47.8% of the population is irreligious (atheist, agnostic or other irreligious life stances), while 21.3% of the population are believers. The religious identity of the country has changed drastically since the first half of the 20th century, when more than 90% of Czechs were Christians. As of 2021, 11.7% of the population identified with Christianity (9.3% identifying with Catholicism and 2.4% with all other Christian denominations); 10.8% identified with other religious identities or beliefs. According to sociologist Jan Spousta, not all the irreligious people are atheists; indeed, since the late 20th century there has been an increasing distancing from both Christian dogmatism and atheism, and at the same time ideas and non-institutional models similar to those of Eastern religions have become widespread through movements started by various gurus, and hermetic and mystical paths.

Protestantism is a branch of Christianity that emphasizes justification of sinners through faith alone, the teaching that salvation comes by unmerited divine grace, the priesthood of all believers, and the Bible as the sole infallible source of authority for Christian faith and practice. The five solae summarize the basic theological beliefs of mainstream Protestantism.

Protestants follow the theological tenets of the Protestant Reformation, a movement that began in the 16th century with the goal of reforming the Catholic Church from perceived errors, abuses, and discrepancies. The Reformation began in the Holy Roman Empire in 1517, when Martin Luther published his Ninety-five Theses as a reaction against abuses in the sale of indulgences by the Catholic Church, which purported to offer the remission of the temporal punishment of sins to their purchasers. Luther's statements questioned the Catholic Church's role as negotiator between people and God, especially when it came to the indulgence arrangement, which in part granted people the power to purchase a certificate of pardon for the penalization of their sins. Luther argued against the practice of buying or earning forgiveness, claiming instead that salvation is a gift God gives to those who have faith.

According to a Pew estimation in 2025, Christians made up to 2.3 billion of the worldwide population of about 8 billion people. This represents nearly one-third of the world's population and is the largest religion in the world, with the three largest groups of Christians being the Catholic Church, Protestantism, and the Eastern Orthodox Church. The largest Christian denomination is the Catholic Church, with 1.3 billion baptized members. The second largest Christian branch is either Protestantism (if it is considered a single group), or the Eastern Orthodox Church (if Protestants are considered to be divided into multiple denominations).

According to a 2020 Pew Research Center study, of the then 201 countries and territories, 120 had Christian majorities, four fewer than in the 2010 study.