The Rashidun Caliphate (Arabic: اَلْخِلَافَةُ ٱلرَّاشِدَةُ, romanized: al-Khilāfah ar-Rāšidah; 632 – 661) was the first caliphate to succeed the Islamic prophet Muhammad. It was ruled by the first four successive caliphs of Muhammad after his death in 632 CE (11 AH). During its existence, the empire was the most powerful economic, cultural, and military force in West Asia.

The caliphate arose following Muhammad’s passing in June 632 and the subsequent debate over the succession to his leadership. Muhammad's close companion Abu Bakr (r. 632–634), of the Banu Taym clan, was elected the first caliph in Medina and he began the conquest of the Arabian Peninsula. His brief reign ended in August 634 when he died and was succeeded by Umar (r. 634–644), his appointed successor from the Banu Adi clan. Under Umar, the caliphate expanded at an unprecedented rate, ruling more than two-thirds of the Byzantine Empire and nearly the entire Sasanian Empire. Umar was assassinated in November 644 and was succeeded by Uthman (r. 644–656), a member of the Banu Umayya clan, who was elected by a six-person committee arranged by Umar. Under Uthman, the caliphate concluded its conquest of Persia in 651 and continued expeditions into the Byzantine territories. Uthman's nepotistic policies earned him vehement opposition from some Muslim generals and he was eventually assassinated by rebels in June 656.

He was subsequently succeeded by Ali (r. 656–661), a member of Muhammad's Banu Hashim clan, who transferred the capital to Kufa. Ali presided over the civil war called the First Fitna as his suzerainty was unrecognized by Uthman's kinsman and Syria's governor Mu'awiya I (r. 661–680), who believed that Uthman was unlawfully killed and his murderers should be punished. Additionally, a third faction known as Kharijites, who were former supporters of Ali, rebelled against both Ali and Mu'awiya after refusing to accept the arbitration in the Battle of Siffin. The war led to the overthrow of the Rashidun Caliphate and the establishment of the Umayyad Caliphate in 661 by Mu'awiya. The civil war permanently consolidated the divide between Sunni and Shia Muslims, with Shia Muslims believing Ali to be the first rightful caliph and Imam after Muhammad, favouring his bloodline connection to Muhammad.

The Rashidun Caliphate is characterized by a twenty-five-year period of rapid military expansion followed by a five-year period of internal strife. The Rashidun Army numbered more than 100,000 men at its peak. By the 650s, in addition to the Arabian Peninsula, the caliphate had subjugated the Levant to the Transcaucasus in the north; North Africa from Egypt to present-day Tunisia in the west; and the Iranian Plateau to parts of Central Asia and South Asia in the east. The four Rashidun caliphs were chosen by a small electoral body consisting of prominent members of the Quraysh tribal confederation called shūrā (Arabic: شُـوْرَى, lit. 'consultation').