Muhammad (Arabic: مُحَمَّد‎, pronounced [muħammad]; c. 570 CE – 8 June 632 CE) was an Arab religious, social and political leader and the founder of Islam  According to Islamic doctrine, he was a prophet, sent to present and confirm the monotheistic teachings preached previously by Adam, Abraham, Moses, Jesus, and other prophets. He is viewed as the final prophet of God in all the main branches of Islam, though some modern denominations diverge from this belief. Muhammad united Arabia into a single Muslim polity, with the Quran as well as his teachings and practices forming the basis of Islamic religious belief. He is referred to by many appellations, including Messenger of Allah, The Prophet Muhammad, Allah's Apostle, Last Prophet of Islam and others; there are also many variant spellings of Muhammad, such as Mohamet, Mahamad, Muhamad and many others.

Born approximately 570 CE (Year of the Elephant) in the Arabian city of Mecca, Muhammad was orphaned at the age of six. He was raised under the care of his paternal grandfather Abd al-Muttalib, and upon his death, by his uncle Abu Talib. In later years he would periodically seclude himself in a mountain cave named Hira for several nights of prayer. When he was 40, Muhammad reported being visited by Gabriel in the cave, and receiving his first revelation from God. Three years later, in 610, Muhammad started preaching these revelations publicly, proclaiming that "God is One", that complete "submission" (islām) to God is the right way of life (dīn), and that he was a prophet and messenger of God, similar to the other prophets in Islam.

The followers of Muhammad were initially few in number, and experienced hostility from Meccan polytheists. He sent some of his followers to Abyssinia in 615 to shield them from prosecution, before he and his followers migrated from Mecca to Medina (then known as Yathrib) in 622. This event, the Hijra, marks the beginning of the Islamic calendar, also known as the Hijri Calendar. In Medina, Muhammad united the tribes under the Constitution of Medina. In December 629, after eight years of intermittent fighting with Meccan tribes, Muhammad gathered an army of 10,000 Muslim converts and marched on the city of Mecca. The conquest went largely uncontested and Muhammad seized the city with little bloodshed. In 632, a few months after returning from the Farewell Pilgrimage, he fell ill and died. By the time of his death, most of the Arabian Peninsula had converted to Islam

The revelations (each known as Ayah — literally, "Sign [of God]") that Muhammad reported receiving until his death form the verses of the Quran, regarded by Muslims as the verbatim "Word of God" on which the religion is based. Besides the Quran, Muhammad's teachings and practices (sunnah), found in the Hadith and sira (biography) literature, are also upheld and used as sources of Islamic law (see Sharia).