The U.S. government estimates the population at 85.0 million (midyear 2020 estimate). According to Iranian government estimates, Muslims constitute 99.4 percent of the population, of whom 90-95 percent are Shia, and 5-10 percent are Sunni, mostly Turkmen, Arabs, Baluchis, and Kurds, living in the northeast, southwest, southeast, and northwest provinces, respectively. Afghan refugees, economic migrants, and displaced persons also make up a significant Sunni population, but accurate statistics on the breakdown of the Afghan refugee population between Sunni and Shia are unavailable. There are no official statistics available on the number of Muslims who practice Sufism, although unofficial reports estimate several million.

According to U.S. government estimates, groups constituting the remaining less than 1 percent of the population include Baha’is, Christians, Yarsanis, Jews, Sabean-Mandaeans, and Zoroastrians. The three largest non-Muslim minorities are Baha’is, Christians, and Yarsanis.

According to Human Rights Watch data, Baha’is number at least 300,000.

The government Statistical Center of Iran reports there are 117,700 Christians in the country. Some estimates, however, suggest there may be many more than actually reported. According to World Christian Database statistics, there are approximately 547,000 Christians. Elam Ministries, a Christian organization, estimates there could be between 300,000 and one million.

Estimates by the Assyrian Church of the total Assyrian and Chaldean Christian population put their combined number at 7,000. There are also Protestant denominations, including evangelical groups, but there is no authoritative data on their numbers. Christian groups outside the country disagree on the size of the Protestant community, with some estimates citing figures lower than 10,000, and others, such as Open Doors USA, citing numbers greater than 800,000. Many Protestants and converts to Christianity from Islam reportedly practice in secret.

There is no official count of Yarsanis, but HRANA and the Center for Human Rights in Iran (CHRI) estimate there are up to two million. Yarsanis are mainly located in Loristan and the Kurdish regions.

According to recent estimates from Armenian Christians who maintain contact with the Iranian Christian community in the country, their current numbers are approximately 40,000 to 50,000, significantly lower than the peak of 300,000 estimated prior to 1979. The number of Roman Catholics in the country is estimated to be 21,000.

According to Zoroastrian groups and the government-run Statistical Center of Iran, the population includes approximately 25,000 Zoroastrians.

According to the Tehran Jewish Committee, the population includes approximately 9,000 Jews, while representatives from the Jewish community in the country estimated their number at 15,000 during a 2018 PBS News Hour interview.

The population, according to government media, includes 14,000 Sabean-Mandaeans.

According to the 2011 census, the number of individuals who are nonreligious rose by 20 percent between 2006 and 2011, which supports observations by academics and others that the number of atheists, agnostics, nonbelievers, and religiously unaffiliated living in the country is growing. Often these groups, however, do not publicly identify, as documented by Amnesty International’s report on the country, because those who profess atheism are at risk of arbitrary detention, torture, and the death penalty for “apostasy.”

The U.S. government estimates the total population at 38.9 million (midyear 2019 estimate). According to 2010 government statistics – the most recent available – 97 percent of the population is Muslim. Shia Muslims, predominantly Arabs but also including Turkoman, Faili (Shia) Kurds, and others, constitute 55 to 60 percent of the population. Sunni Muslims are approximately 40 percent of the population, of which Arabs constitute 24 percent, Kurds 15 percent, and Turkomans the remaining 1 percent. Shia, although predominantly located in the south and east, are the majority in Baghdad and have communities in most parts of the country. Sunnis form the majority in the west, center, and north of the country.

According to Christian leaders as well as NGO and media reports, fewer than 250,000 Christians remain in the country, down from a pre-2002 population estimate of between 800,000 and 1.4 million persons. Approximately 67 percent of Christians are Chaldean Catholics (an eastern rite of the Roman Catholic Church), and nearly 20 percent are members of the Assyrian Church of the East. The remainder are Syriac Orthodox, Syriac Catholic, Armenian Catholic, Armenian Apostolic, Anglican, and other Protestants. There are approximately 2,000 registered members of evangelical Christian churches in the IKR, while an unknown number, mostly converts from Islam, practice secretly.

Yezidi leaders continue to report that most of the 400,000 to 500,000 Yezidis in the country reside in the north, with approximately 200,000 to 230,000 remaining displaced as of October 2020. The Shabak number between 350,000 and 400,000, three-fourths of whom are Shia. Most Sunni Shabak and some Shia Shabak reside in Ninewa. According to Kaka’i (also known as Yarsani) activists, their community has approximately 120,000 to 150,000 members located in the Ninewa Plain and in villages southeast of Kirkuk as well as in Diyala and Erbil. Estimates of the size of the Sabean-Mandean community vary, but according to Sabean-Mandean leaders, 10,000 to 15,000 members remain in Iraq, mainly in the south, with between 750 and 1,000 in the IKR and Baghdad. Armenian leaders report a population of approximately 7,000 Armenian Christians, both Armenian Apostolic Church (Armenian Orthodox) and Armenian Catholic. Baha’i leaders report fewer than 2,000 members, spread throughout the country in small groups, including approximately 500 in the IKR.

There are fewer than six adult members in the Baghdad Jewish community, according to a local Jewish community leader. In the IKR, there are approximately 80 Jewish families, according to the KRG international advocacy coordinator, although some Jewish families do not openly acknowledge their religion for fear of persecution, according to the KRG Ministry of Endowment and Religious Affairs (MERA) and NGO sources, and the number could be higher. According to the KRG MERA, there are approximately 60 Zoroastrian families in the IKR. Zoroastrian sources report there are approximately 20,000 to 25,000 Zoroastrians in the country.

According to the International Organization for Migration (IOM), approximately 1.2 million persons remain displaced within the country, predominantly in Ninewa, Dohuk, Erbil, Sulaymaniyah, and Kirkuk Governorates, compared with 1.5 million persons at the end of 2019. According to the KRG’s Joint Crisis Coordination Center, there are approximately 700,000 internally displaced persons (IDPs) in the IKR. Forty percent of IDPs throughout the country are Sunni Arabs, 30 percent Yezidis, 13 percent Kurds (of several religious affiliations), and 7 percent Christians. Other religious minorities comprise the remaining 10 percent.

According to the IOM, there were more than 205,000 IDPs in camps and approximately 104,000 in critical shelters throughout the country at year’s end.