Islam: Sunnis and Shiites

The majority of the world’s Muslim population follows the Sunni branch of Islam, and approximately 10-15% of all Muslims follow the Shiite (Shi‘ite, Shi‘a, Shia) branch. Shiite populations constitute a majority in Iran, Iraq, Bahrain, and Azerbaijan. There are also significant Shiite populations in Afghanistan, Kuwait, Lebanon, Pakistan, Saudi Arabia, Syria, and Yemen. Sunnis and Shiites share most basic religious tenets. However, their differences sometimes have been the basis for religious intolerance, political infighting, and violent confrontations. This report includes a historical background of the Sunni-Shiite split and the differences in religious beliefs and practices between and within each Islamic sect as well as their similarities. The report also relates Sunni and Shiite religious beliefs to current discussions of Islamic terrorist groups, Iraq, and other issues of interest to the 109 Congress. This report will not be updated. Related CRS products include CRS Report RS21432 and CRS Report RS21695.