As per the 2011 census, the predominant religion in Lithuania is Christianity, with the largest confession being that of the Catholic Church. In the early 21st century, about 77% of the population is Catholic according to the 2011 census. There are also smaller groups of Orthodox Christians, Evangelical Lutherans, members of Reformed churches, other Protestants, Jews and Muslims as well as people of other faiths. Some elements of the ancient Lithuanian pagan religion survive in the countryside, mingled with Christianity.
According to the 2010 Eurobarometer Poll, 47% of Lithuanian citizens responded that "they believe there is a God", 37% answered that "they believe there is some sort of spirit or life force", and 12% said that "they do not believe there is any sort of spirit, god, or life force".
The first census in independent Lithuania, in 1923, established the fallowing religious distribution: Catholic -- 85.7 per cent; Jews -- 7.7 per cent; Protestant -- 3.8 per cent; Greek Orthodox -- 2.7 per cent.
As per the 2011 census:
As per the 2011 census, 77.2% of Lithuanians belong to the Catholic Church.  Catholic Church has claimed the adherence of the majority of Lithuania since the Christianization of Lithuania in the 14th and 15th centuries. Lithuania kept her Catholic identity under the Russian Empire and later under the Soviet Union when some Catholic priests led the resistance against the Communist regime, which is commemorated in the Hill of Crosses near ?iauliai, a shrine to the anti-communist resistance. Political activity has continued after independence against socialism and liberalism, especially in ethical questions.
The center of Greek Catholic life in Lithuania is the Basilian Monastery and Church of the Holy Trinity in Vilnius. In the past, the monastery was multiethnic but now serves a mostly Ukrainian community. 
Protestants are 0.8%, of which 0.6% are Lutheran and 0.2% are Reformed. According to Losch (1932), the Lutherans were 3.3% of the total population; they were mainly Germans in the Memel territory (now Klaip?da). There was also a tiny Reformed community (0.5%) which still persists. Protestantism has declined with the removal of the German population, and today it is mainly represented by ethnic Lithuanians throughout the northern and western parts of the country, as well as large urban areas. Believers and clergy suffered greatly during the Soviet occupation, with many killed, tortured or deported to Siberia. Newly arriving evangelical churches have established missions in Lithuania since 1990.
Lutheranism in Lithuania dates back to the 16th century, when it came mainly from the neighbouring German-controlled areas of Livonia and East Prussia. A Synod in Vilnius united the church in 1557. The parish network covered nearly all of the Grand Duchy, with district centers in Vilnius, Kedainai, Bir?ai, Slucke, Kojdanove and Zabludove later Izabeline. Small Protestant communities are dispersed throughout the northern and western parts of the country.
The majority of Prussian Lithuanians living in East Prussia and in Memelland (since 1945 the Klaip?da Region of Lithuania) belonged to the Evangelical Church of the old-Prussian Union. Most resettled in the West Germany after World War II along with the ethnic German inhabitants.
Since 1945, Lutheranism in Lithuania has declined largely due to the ongoing secularization that sweeps throughout Europe.
The Lithuanian Evangelical Reformed Church is a historic denomination it was founded in 1557. Notable member was Szymon Zajcusz. In the second half of the 16th century the Unitarians separated. The denomination has over 7000 members in 14 congregations. The church is a member of the World Communion of Reformed Churches and the World Reformed Fellowship
Most of Armenians in Lithuania, making up about 0.1% of population according to own estimates belong to the Armenian Apostolic Church, which is often classified as an Oriental Orthodox Church, in distinction from Eastern Orthodox (to which the main Russian, Greek and Georgian Churches belong).
An Armenian Apostolic Church St. Vardan was opened in Vilnius in 2006.
In Lithuania, Islam has a long history unlike many other northern European countries. The medieval Grand Duchy of Lithuania of the Polish-Lithuanian Commonwealth allowed Muslims, notably the Crimean Tatars to settle in the lands in the south. Some of people from those lands were moved into ethnically Lithuanian lands, now the current Republic of Lithuania, mainly under rule of Grand Duke Vytautas. The Tatars, now referred to as Lithuanian Tatars, lost their language over time and now speak Lithuanian as natives; however, they have strongly maintained their Muslim faith.
The Lithuanian Jewish community has roots that go back to before the time of the Grand Duchy of Lithuania. Lithuania was historically home to a large Jewish community and an important center of Jewish scholarship and culture from the 18th century until the community was almost entirely eliminated during the Holocaust. Before World War II, the Lithuanian Jewish population numbered some 160,000, about 7% of the total population.Vilnius alone had a Jewish community of nearly 100,000, about 45% of the city's total population with over 110 synagogues and 10 yeshivot in the city.
According to a Karaite tradition several hundred Crimean Karaites were invited to Lithuania by Grand Duke Vytautas to settle in Trakai ca. 1397. A small community remains in Trakai today, which has preserved the Turkic Karaim language and distinctive customs, such as its traditional dish called "kibinai", a sort of meat pastry, and its houses with three windows, one for God, one for the family, and one for Grand Duke Vytautas.
Medieval Lithuania was the last pagan nation in Europe, officially converting in the 14th century. The neo-pagan movement Romuva, established in 1967, attempts to reconstruct and revive Lithuanian paganism.