The dominant religion in Kurdistan is Sunni Islam. Other prominent religious traditions in the region include Shia Islam, Yazidism, Yarsanism, Zoroastrianism, and Christianity, while Judaism was also a significant minority religion in Kurdistan until the Jewish exodus from the Muslim world in the 20th century.

According to a 2016 estimate by the Kurdish Institute of Paris, Kurdistan's total population is approximately 34.5 million people, including Kurds, Turks, Arabs, Assyrians, Armenians, and Yazidis, among other ethnic groups, contributing to the region's religious diversity.

Islam

The majority of Kurdish people are Muslims. While the relationship between religion and nationalism has usually been strained and ambivalent with the strong hold of the Islamic leaders in Kurdish society, it has generally been the conservative Muslim Kurds who formed the backbone of Kurdish nationalist movements. According to van Bruinessen, Kurdish identity was largely tribal and defined by Sunni Islam until the rise of nationalism in the later Ottoman Empire,van Bruinessen, Martin. Agha, Shaikh and State: The Social and Political Structures of Kurdistan. Zed Books, 1992, pp. 23–24. although historic leaders such as Idris Bitlisi or Sharafkhan Bitlisi may have exaggerated the Sunni tendencies among the Kurds as to disspell any doubts about their loyalty to the Ottomans.Evliya Çelebi in Diyarbekir: The Relevant Section of the Seyahatname. Edited with Translation, Commentary and Introduction, 2023, pp. 14, .

As of 2023 in Iraqi Kurdistan, Nabaz Ismail, the spokesperson for the autonomous region's Ministry of Endowments and Religious Affairs, estimates the total number of mosques to stand at 5,820, with 3,380 (58%) of them offering Friday sermons, and 129 mosques opening in one year, including 56 in the regional capital city, Erbil. He further states that the ministry employs 2,700 Islamic teachers and operates 100 Quran memorization centers as well 21 Islamic schools. Nabaz Ismail also says that 99% of the mosques have been built through philanthropy, relying on private donors and their charity in the form of zakat or sadaqah.

Self-identification as Muslim first Based on cross-national comparative surveys conducted in 2011 and 2013, it has been found out that when asked about what constitute their most important identity ("above all"), among the Kurds of Turkey 66% chose Muslim, 20% chose the Kurdish identity and 11% the Turkish nation, while among the Kurds of Iraq, 59% chose Muslim, 27% went for their Kurdish identity and 13% chose the Iraqi nation.

Sunni Islam The majority of Kurds are Sunni Muslims. The exact proportion is uncertain but McDowall gives the percentage as "approximately 75%", while Martin van Bruinessen estimates around two-thirds or three-quarters at least. Most Sunni Kurds follow the Shafi‘i school, which distinguishes them from Arab and Turkish neighbors who in general are Hanafi. This difference is identified by some Kurds as being essential to their ethnic identity and deliberately emphasized.

During the last six centuries, the Kurdish ulama had an influential role in the Ottoman court and taught at important universities like Al-Azhar University and in the Holy Cities of Arabia, Medina and Mecca. Moreover, due to the location of Kurdistan between the three major cultural Islamic regions, many Kurdish ulama not only knew Kurdish, but also Arabic, Persian, and Turkish, giving them an important role in mediating between Indian Muslims who communicated in Persian, Arabic, and Turkish. Kurdish ulama teachings also had a lasting impact in Indonesia.

Sunni Islam among Kurds is characterized by a strong overtone of mysticism and its scholars’ affiliation with Sufi orders. In Kurdish society these constitute a hierarchical system, in which the leaders (sheikh) deploy their influence onto the localities through their deputies (khalifa), who mediate between sheikhs and common people. Today, Naqshbandiya and Qadiriyya are the most active tariqas. These tariqas had produced numbers of significant figures in the early history of Kurdish nationalist movements, including Mahmud Barzanji of Qadiriyyah, and Sheikh Said and Sheikh Ubeydullah of Naqshbandiya. Strong influences of sheikhs in the late 19th and the early 20th centuries were attributed to the Ottoman administrative reforms and the defense against the intrusion of Christian missionaries.

Modern political development among Sunni Muslim Kurds varies throughout the state to which they belong. In Turkey, Said Nursi exerted major influence. Nursi devoted himself to intellectual development. This became the basis of the Nur Movement which espoused Islamic Modernism, mysticism, compatibility with modern science, and tolerance. The Nur movement garnered several million followings in the mid 20th century.Paul Dumont "Disciples of the Light: The Nurju Movement in Turkey," Central Asian Survey 5:2 (1986): 330. The group fragmented substantially in the 1970s and 1980s, resulting in offshoots such as the Gülen movement.

Shia Islam There is a minority of Twelver Shi'i Muslims in southern parts of Kurdistan in Kermanshah province, Khanaqin, Mandali, and Ilam province. The proportion of Kurds who ascribe to Twelverism is potentially up to 15%. Historically, there was also a small community of Zaydi Kurds in Iraq.كتاب دائرة المعارف: من سليكون الى صلاح الدينية. ١٠, Volume 10, Buṭrus al- Bustānī, 1898, pp. 614 In Iraqi Kurdistan, there were several Shia influenced groups, including the Feyli Kurds, Kaka'is, and Shabaks.Ayatollahs, Sufis and Ideologues: State, Religion and Social Movements in Iraq, 2002, pp. 126, .

An Alevi community mostly live in north western parts of Kurdistan. They are mostly concentrated in Tunceli Province.

Influence on Kurdish identity While studying youth religiosity in Iraqi Kurdistan, Kurdish sociologist Ibrahim Sadiq Malazada through his 2021 empirical research estimates the religious youth to stand at around 50%, or roughly half, noting that the rise of the Islamic State has had no real impact (with 8-9% decreasing their religiosity but 7% increasing due to ISIS), while COVID-19 instead strengthened religiosity (as 29% consider it "a divine test for society"), Malazada concluding that the "religious identity among youth in Kurdistan tended to be stable and that there has been no significant change in the religious tendencies of young people." As per the same research, 30% of the young Kurds consider their religious identity as being as important as their national identity, 29% consider their religious identity to be more important while 7% consider religion as "the only remaining source of pride."

There are also concerns about youth radicalization because of the worsening socio-economic conditions in Iraqi Kurdistan, even though they go for a quietist form of Salafism, often favored by the local parties in order to reduce the influence of Muslim Brotherhood–affiliated groups, instead of the more violent and revolutionary Salafi jihadism. Salafism among Kurds is a phenomenon going beyond the youth in Iraqi Kurdistan.

Yazidism

Yazidism is a monotheistic ethnic religion with roots in a western branch of an Iranic pre-Zoroastrian religion. It is based on the belief of one God who created the world and entrusted it into the care of seven Holy Beings. The leader of this heptad is Tawûsê Melek, who is symbolized with a peacock. Its adherents number from 700,000 to 1 million worldwide and are indigenous to the Kurdish regions of Iraq, Syria and Turkey, with some significant, more recent communities in Russia, Georgia and Armenia established by refugees fleeing Muslim persecution in Ottoman Empire. Yazidism shares with Kurdish Alevism and Yarsanism a lot of similarities that date back to pre-Islam.

Yarsanism

Yarsanism (also known as Ahl-I-Haqq, Ahl-e-Hagh or Kakai) is also one of the religions that are associated with Kurdistan.

Although most of the sacred Yarsan texts are in the Gorani and all of the Yarsan holy places are located in Kurdistan, followers of this religion are also found in other regions. For example, while there are more than 300,000 Yarsani in Iraqi Kurdistan, there are more than 2 million Yarsani in Iran. However, the Yarsani lack political rights in both countries.

During the war with ISIL, many Yarsani followers were persecuted by the Islamic State, being considered as “heretics” and being driven away from their villages. However, Peshmerga offensives have drove out the Islamic State, and the Yarsani people now enjoy relative safety.

Zoroastrianism Zoroastrianism was one of the dominant religions in Kurdistan before the Islamic era. Currently, Zoroastrianism is an officially recognized religion in Iraqi Kurdistan and Iran and two Zoroastrian temples have opened in Iraqi Kurdistan after the official recognition of Zoroastrianism in the region in 2015. There was a trend of Zoroastrianism in 2015 as well, where many accepted Zoroastrianism after being disillusioned with Islam because of the Islamic State. Most Kurds who converted to Zoroastrianism did so because they considered it a native religion and more welcoming than Islam, but many Kurds also did convert to Zoroastrianism out of genuine conviction.Dick, Samme. Rekindling the Flame: Zoroastrianism in Iraqi Kurdistan, Religion, State and Society, 2022. pp. 12–19. Some non-Kurds also converted to Zoroastrianism.Kurdish Studies Archive: Vol. 7 No. 2 2019, 2024, pp. 201, Martin van Bruinessen, A Kurdish Islamic cleric from Sulaymaniyah, on the other hand, claimed that Zoroastrianism was not the ancestral religion of Kurds and that it was forced on them by "fire-worshipping Persians", whereas Islam freed them. He then called on Kurds to kill Zoroastrian converts if they do not convert back to Islam within three days of their conversion. On 21 September 2016, the first official Zoroastrian fire temple of Iraqi Kurdistan opened in Sulaymaniyah.

The Zoroastrian community in Iraqi Kurdistan has claimed that thousands of people have recently converted to Zoroastrianism in the region; however, this has not been confirmed by independent sources. In 2020, it was reported that there are 120 Zoroastrians in Iraqi Kurdistan.

Christianity

Christianity is present in the Kurdistan Region of Iraq through the presence of several distinct communities. Most are Assyrians, who practice under a multitude of denominations such as the Assyrian Church of the East, the Chaldean Catholic Church, and the Syriac Orthodox Church. Other Christian communities include Armenians, and the Kurdish Christian minority. The Assyrian and Armenian communities in the Kurdistan Region of Iraq live primarily in the Erbil and Dohuk Governorates.

Judaism

There used to be a Jewish minority in most parts of Kurdistan, but most of them were forced to flee to Israel in the mid-20th century. At the beginning of the 20th century, the cities of Kermanshah, Orumieh, Piranshahr and Mahabad had the largest Jewish populations in Iranian Kurdistan.

According to recent reports, there were between 400 and 730 Jewish families living in the Kurdish region. However, Dr. Mordechai Zaken, an Israeli expert on Kurdish affairs, told the Jerusalem Post in November 2015 interview that the media reports on 430 Jewish families in Iraqi Kurdistan were false: "There were several dozen families that had some distant family connection to Judaism and most of them immigrated to Israel in the aftermath of the Gulf War...".