Grand Ayatollah Sayyid Ali Hoseyni Khāmene’i (علی حسینی خامنه‌ای, pronunciation (help·info) born 17 July 1939), also known as Ali Khamenei, is an Iranian politician and cleric. He has been Supreme Leader of Iran since 1989 and before that was president of Iran from 1981 to 1989. He has been described as one of only three people having "important influences" on the Islamic Republic of Iran, the other two being Ayatollah Ruhollah Khomeini, leader of the revolution, and Ayatollah Akbar Hashemi Rafsanjani, president of Iran for much of the 1990s. Currently, Khamenei is the commander-in-chief of the armed forces of Iran.

Born to an Iranian Azeri father and a Yazd-native mother in Mashhad, Ali Khamenei began religious studies before completing elementary education.

The son of a cleric, he is second eldest of eight children, and two of his brothers are also clerics. His younger brother, Hadi Khamenei, is a notable newspaper editor and cleric.