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Religion

Baghdad's population was estimated at 7.22 million in 2015. The city historically has a predominantly Sunni population, but by the early 21st century around 52% of the city's population were Iraqi Shi'ites. At the beginning of the 21st century, some 1.5 million people migrated to Baghdad. Sunni Muslims make up 29–34% of Iraq's population and they are still a majority in west and north Iraq. As early as 2003, about 20 percent of the population of the city was the result of mixed marriages between Shi'ites and Sunnis. Following the civil war between the Sunni and Shia militia groups during the U.S. occupation of Iraq, the population of Sunnis significantly decreased as they were pushed out of many neighborhoods. The 2013–2017 war following the Islamic State's invasion in 2014 caused hundreds of thousands of Iraqi internally displaced people to flee to the city.

The majority of the citizens are Muslims with minorities of Christians, Yezidis, Jews and Mandeans also present. There are many religious centers distributed around the city including mosques, churches, synagogues and Mashkhannas cultic huts. Masjid Al-Kadhimain is a shrine that is located in the Kādhimayn suburb of Baghdad. It contains the tombs of the seventh and ninth Twelver Shi'ite Imams, Musa al-Kadhim and Muhammad at-Taqi respectively, upon whom the title of Kādhimayn ("Two who swallow their anger") was bestowed. Many Shi'ites travel to the mosque from far away places to commemorate those imams.

Prior to the 2003 invasion by the United States, Baghdad was home to tiny Jewish community of 450. It started declining since 1940s, following establishment of Israel. The Jews of Baghdad faced restrictions until 1980s, when Saddam took power and granted freedom and protection to them. The Iraqi Jewish population declined after the 2003–2011 war and the subsequent 2013–2017 war. The Meir Taweig Synagogue is the only synagogue remaining in Baghdad. In the Kadhimiya district of Baghdad, was the house of Baháʼu'lláh, (Prophet Founder of the Baha'i Faith) also known as the "Most Great House" (Bayt-i-A ʻ zam) and the "House of God," where Baháʼu'lláh mostly resided from 1853 to 1863. It is considered a holy place and a place of pilgrimage by Baha'i's according to their " Most Holy Book ". On 23 June 2013, the house was destroyed under unclear circumstances.