چكيده فارسي :
The majority of the world‟s Muslim population follows the Snni and approximately 10-15% of all Muslims follow the Shia (Shi‟ite, Shi‟a, shiite) branch. Shiite populations constitute a majority in Iran, Iraq, Bahrain, and Azerbaijan. There are significant Shia populations in Afghanistan, Kuwait, Lebanon, Pakistan, Saudi Arabia, Syria, and Yemen. Sunnis and Shias share most basic religious tenets. Their differences sometimes have been the basis for religious intolerance, political fighting, and sectarian rage and violence. This article includes a historical background of the Sunni-Shia and discusses the differences in religious beliefs and practices between and within each Islamic sect as well as their similarities. This article relates Sunni and Shia religious beliefs to discussions of terrorism and sectarian violence. In this article, the researcher tried to make a review on Islam and its branches, beliefs, forming and practices of each other.