Sunni and Shi’a Islam: what is the difference?

When Muhammad died, the community had to choose a leader. The group that became the Sunnis accepted Abu Bakr, a close companion, as the first caliph, followed by Umar, Uthman and Ali.

The group that became the Shi’a held that Muhammad had designated his cousin and son-in-law Ali as his successor. The word Shi’a comes from shi’at Ali, “the party of Ali.” Ali did eventually become the fourth caliph, but conflict followed. In 680 CE, Ali’s son Husayn and many of his family were killed at the Battle of Karbala, an event that became central to Shi’a religious memory.

Sunni comes from ahl al-sunna wa al-jama’a, “the people of the tradition and the community.” Sunni Islam emphasizes following the example of the Prophet and the consensus of the community. Religious authority rests with scholars trained in law and theology, rather than with an infallible leader.

Shi’a Islam teaches that leadership of the community belongs to Imams descended from Muhammad through Ali and Fatima. For Twelver Shi’a, the largest Shi’a group, there were twelve Imams, the last of whom, Muhammad al-Mahdi, went into hiding in the ninth century and will return at the end of time.

Shi’a teaching holds that the Imams were divinely guided and protected from error. In their absence, senior scholars, such as ayatollahs and maraji’, provide guidance. Other Shi’a branches include the Ismailis and the Zaydis, who recognize different lines of Imams.

Both branches take the Quran as the first source of law. For the sunnah, Sunnis rely on hadith collections such as those of al-Bukhari and Muslim, transmitted through the Prophet’s companions. Shi’a Muslims rely on collections such as al-Kafi, transmitted largely through the Imams, and give the Imams’ teachings authority alongside the Prophet’s.

Sunni Islam has four main schools of law: Hanafi, Maliki, Shafi’i and Hanbali. Twelver Shi’a follow the Ja’fari school, named after the sixth Imam, Ja’far al-Sadiq.

Most practices are shared, but there are visible differences. Many Shi’a Muslims combine the five daily prayers into three time periods and pray placing the forehead on a small tablet of clay, often from Karbala. The call to prayer used by Shi’a communities includes an additional phrase about Ali. Shi’a Muslims pay khums, a religious tax, in addition to zakat.

Shi’a Muslims commemorate the martyrdom of Husayn during the month of Muharram, culminating on the day of Ashura, with mourning gatherings and processions. Sunnis also regard Ashura as significant, often marking it with fasting. Shi’a Muslims also make pilgrimage to the shrines of Imams, such as those in Karbala, Najaf and Mashhad.

Sunnis form the majority in most Muslim-majority countries. Shi’a Muslims form majorities in Iran, Iraq, Azerbaijan and Bahrain and large communities in Lebanon, Pakistan, India, Afghanistan, Saudi Arabia and Yemen.

Sunni and Shi’a Muslims pray at the same holy sites in Mecca and Medina and often live, work and intermarry together. Political conflicts in the modern Middle East have sometimes been framed in sectarian terms, but many scholars stress that these conflicts are driven by politics as much as theology. The 2005 Amman Message, endorsed by scholars from both branches, recognized the major Sunni and Shi’a schools as valid forms of Islam.

Sunni and Shi’a Muslims share Islam’s core beliefs and practices. They differ over succession to Muhammad, the authority of the Imams, hadith collections, schools of law and some ritual details. Sunnis follow the consensus of the community and its scholars; Shi’a Muslims follow the line of Imams from the Prophet’s family.