There are many active religions in Luxembourg. The most important, in terms of size of congregation and historical importance, is Roman Catholicism, but the state does not support, or discriminate against, any one single religion.
Since 1979 it has been illegal for the government to collect statistics on religious beliefs or practices. It is estimated by the CIA Factbook that 87% of Luxembourgers are Roman Catholics, the remaining 13% being made up of Protestants, Eastern Orthodox Christians, Jews, Muslims and those of other or no religion.
Luxembourg is a secular state, but the Grand Duchy recognises and supports several denominations, in exchange for which, the state is allowed a hand in their affairs. This status, first afforded to the Roman Catholic Church, stems from Napoleon's Concordat of 1801, the principles of which have continued to apply to Luxembourg, despite its separation from France in 1815 and its subsequent Dutch ownership.
Despite having the same roots as France's official position of laïcité, Luxembourg's approach to religion has taken a different direction in the past 200 years, reducing the separation of church and state, not increasing it. The state currently recognises Roman Catholicism, Judaism, Greek and Russian Orthodox Christianity, and Protestantism as officially mandated religions. In 2003, representatives of Islam, Anglicanism, and Romanian and Serbian Orthodox Christianity engaged in discussions to be conferred similar status, but without success.
Roman Catholicism is the most practised religion in Luxembourg. Luxembourg was a major centre for Christianity during the Middle Ages, Roman Catholicism was sustained through the Reformation by the hierarchy, buildings, and traditions established in the preceding centuries. The Catholic Church has received state support since 1801.
Protestantism is the largest minority religion in Luxembourg, with estimates of adherents ranging from 5,000 to 15,000 (1% to 3.2% of the population). They are divided across several Protestant churches and creeds, including Lutheranism, Calvinism, Anglicanism, Presbyterianism, and Evangelicalism. The largest Protestant churches in the Grand Duchy are the Protestant Church of Luxembourg (PKL), Protestant Reformed Church of Luxembourg (PRKL), Evangelical Church in Germany, Church of England, and Protestant Church in the Netherlands. The state has supported the PKL since 1894 and the PRKL since 1982.
Luxembourg's Jewish community dates back at least as far as the 13th century, making Judaism the minority religion that has been practised the longest in Luxembourg. Today, Luxembourg's Jews number approximately 1,200, of whom, 650 practise actively. There are very few Orthodox Jews in Luxembourg. During the Holocaust, 1,945 Jewish Luxembourgers were killed, out of a pre-war population of 3,500. Judaism is supported by the state.
In Luxembourg there live about 10,000 to 12,000 Muslims (est. 2009), who represent 2.2% of the total population. In addition, hundreds of Muslims come to work in Luxembourg every workday.
Most Muslims have origins in the Balkans (approximately 60%), while Arab and other Muslim countries represent about 20%. Subsaharan Muslims account for about 5%, and 15% are Europeans.
In the past years, a significant rise in the number of converts has been noticed; the Muslim community of Luxembourg is more and more European.