The Alids are those who claim descent from Ali ibn Abi Talib, the fourth Rashidun caliph and the first imam in Shia Islam. Ali was also the cousin and son-in-law of the Islamic prophet Muhammad. The main branches are the Hasanids and Husaynids, named after Hasan and Husayn, the eldest sons of Ali from his marriage to Fatima, the daughter of Muhammad. As the progeny of Muhammad, they are revered by all Muslims. The Alids have led various movements in Islam, and a line of twelve Alids are the imams in Twelver Shia, the largest Shia branch.

Ali ibn Abi Talib was the cousin and son-in-law of the Islamic prophet Muhammad, and was the fourth Rashidun caliph who ruled from 656 to 661, as well as the first Shia imam. Born to Abu Talib ibn Abd al-Muttalib and Fatima bint Asad, a young Ali was raised by his elder cousin Muhammad and was among the first to accept his teachings.