A caliphate (Arabic: خِلافة khilāfa) is a state ruled by an Islamic leader known as a caliph (Arabic: خَليفة khalīfah audio speaker iconpronunciation ). This is a person considered a political-religious successor to the Islamic prophet, Muhammad, and a leader of the entire Muslim community.

The Rashidun caliphs directly succeeded Muhammad as leaders of the muslim community. They were chosen through shura, a process of community consultation that some think is an early form of Islamic democracy. During the history of Islam after the Rashidun period, many muslim states, mostly hereditary monarchies, have claimed to be caliphates. Caliphs were not thought of as having the same prophetic power as Muhammid did.

In the Sunni branch of Islam a caliph should be elected by Muslims or their representatives. Followers of Shia Islam, however, believe a caliph should be an imam chosen by God from the Ahl al-Bayt (the "Family of the House", Muhammad's direct descendants).