Muslim, 97%; Christian, Jews or other, 3%.
There are no official figures available, mainly due to the highly politically charged nature of the subject. Two estimates of the Muslim proportions of the population are:

The Shi'a are mostly Arabs some Turkmen and Faili Kurds almost all are Twelver school. Sunnis are composed of Arabs, Turkmen who are Hanafi school and Kurds who are Shafi school. According to most western sources the majority of Iraqis are Shi'ite Arab Muslims (around 60%), and Sunnis represent about 40% of the population made up of Arabs, Kurds and Turkmen.

Ethnic Assyrians (most of whom are adherents of the Chaldean Catholic Church and the Assyrian Church of the East) account for most of Iraq's sizable Christian population, along with Armenians. Bahá'ís, Mandaeans, Shabaks, and Yezidis also exist. Most Kurds are Sunni Muslims, although the Faili (Feyli) Kurds are largely Shi'a.