The U.S. government estimates the total population at 19.5 million (July 2018 estimate).  At year’s end there were more than 5.6 million Syrian refugees, primarily Sunni, registered with the Office of the UN High Commissioner for Refugees in neighboring countries and 6.2 million IDPs.  Continued population displacement adds a degree of uncertainty to demographic analyses, but the U.S. government estimates approximately 74 percent of the population is Sunni Muslim, which includes ethnic Arabs, Kurds, Circassians, Chechens, and some Turkomans.  According to U.S. government estimates, other Muslim groups, including Alawites, Ismailis, and Shia, together constitute 13 percent of the population, while Druze constitute 3 percent.

U.S. government estimates put the Christian population at 10 percent of the overall population, although media and other reports of Christians fleeing the country as a result of the civil war suggest the Christian population is now considerably lower.  Before the civil war, there were small Jewish populations in Aleppo and Damascus, and NGOs estimate fewer than 20 Jews remained in the country in 2012.  It is unclear how many, if any, Jews currently reside in Syria.  There was also a Yezidi population of approximately 80,000 before the civil war.

Sunni Muslims are present throughout the country.  Shia Muslims live mostly in rural areas, particularly in several majority-Shia towns in Idlib and Aleppo Provinces.  Twelver Shia generally live in and around Damascus, Aleppo, and Homs.  The majority of Alawites live in the mountainous areas of the coastal Latakia Governorate, but they also have a presence in the cities of Latakia, Tartous, Homs, and Damascus.  The highest concentration of Ismailis is in the city of Salamiyeh, Hama Governorate.

Most Christians belong to autonomous Orthodox churches, the Eastern Catholic (or Uniate) churches (in full communion with the Roman Catholic Church), or the Assyrian Church of the East and other affiliated independent Nestorian churches.  Most Christians continue to live in and around Damascus, Aleppo, Homs, Hama, and Latakia, or in the Hasakah Governorate in the northeast section of the country.  While there were hundreds of thousands of Iraqi Christian refugees before the conflict, the majority of the Iraqi Christian population has since moved to neighboring countries or returned to Iraq.  Many Druze live in the Jabal al-Arab (Jabal al-Druze) region in the southern Governorate of Sweida, where they constitute the majority of the local population.  Yezidis, found primarily in the northeast, also previously lived in Aleppo.