This article is about the history of Iran after the 1979 revolution. For a history of Iran before 1979, see History of Iran.

One of the most dramatic changes in government in Iran's history was seen with the 1979 Iranian Revolution where Shah Mohammad Reza Pahlavi was overthrown and replaced by Ayatollah Ruhollah Khomeini. Autocratic monarchy was replaced by an Islamic Republic based on the principle of rule by Islamic jurists, (or "Velayat-e faqih"), where clerics serve as head of state and in many powerful governmental roles. A pro-Western, pro-American foreign policy was exchanged for one of "neither east nor west", said to rest on the three "pillars" of mandatory veil (hijab) for women, and opposition to the United States and Israel. A rapidly modernizing, capitalist economy was replaced by populist and Islamic economic and cultural policies.