member of one of the two major branches of Islām, the branch that consists of the majority of that religion's adherents. Sunnite Muslims regard their sect as the mainstream and traditionalist branch of Islām, as distinguished from the minority sect, the Shīʿites (Shīʿite).

The Sunnites recognize the first four caliphs as Muḥammad's rightful successors, whereas the Shīʿites believe that Muslim leadership belonged to Muḥammad's son-in-law, ʿAlī, and his descendants alone. In contrast to the Shīʿites, the Sunnites have long conceived of the theocratic state built by Muḥammad as an earthly, temporal dominion and have thus regarded the leadership of Islām as being determined not by divine order or inspiration but by the prevailing political realities of the Muslim world. This led historically to Sunnite acceptance of the leadership of the foremost families of Mecca and to the acceptance of unexceptional and even foreign caliphs, so long as their rule afforded the proper exercise of religion and the maintenance of order. The Sunnites accordingly held that the caliph must be a member of Muḥammad's tribe, the Quraysh, but devised a theory of election that was flexible enough to permit that allegiance be given to the de facto caliph, whatever his origins. The distinctions between the Sunnites and other sects regarding the holding of spiritual and political authority remained firm even after the end of the Caliphate itself in the 13th century.

The Sunnites' orthodoxy is marked by an emphasis on the views and customs of the majority of the community, as distinguished from the views of peripheral groups. The institution of consensus evolved by the Sunnites allowed them to incorporate various customs and usages that arose through ordinary historical development but that nevertheless had no roots in the Qurʾān.

The Sunnites recognize the six “authentic” books of the Ḥadīth, which contain the spoken tradition attributed to Muḥammad. The Sunnites also accept as orthodox one of the four schools of Muslim law. In the 20th century the Sunnites constituted the majority of Muslims in all nations except Iran, Iraq, and perhaps Yemen. They numbered about 900 million in the late 20th century and constituted nine-tenths of all the adherents of Islām.