The 1953 Iranian coup d'état was a significant political event where the democratically elected Prime Minister Mohammad Mosaddegh was overthrown. This coup, occurring on 19 August 1953,^[84] was orchestrated by the United States and the UK, and led by the Iranian army, to strengthen the monarchical rule of Shah Mohammad Reza Pahlavi. It involved U.S. involvement under the name Operation Ajax^[85] and the UK's Operation Boot.^[86] The Shi'a clergy also played a considerable role in this event.^[87]

The root of this political upheaval lay in Mosaddegh's attempts to audit the Anglo-Iranian Oil Company (AIOC, now BP) and limit its control over Iranian oil reserves. His government's decision to nationalize Iran's oil industry and expel foreign corporate representatives led to a global boycott of Iranian oil initiated by Britain,^[88] severely impacting Iran's economy. The UK, under Prime Minister Winston Churchill, and the U.S. Eisenhower administration, fearing Mosaddegh's unyielding stance and concerned about the Tudeh Party's communist influence, decided to overthrow Iran's government.^[89]

Post-coup, General Fazlollah Zahedi's government was established, allowing the Shah to rule with increased authority,^[90] heavily supported by the U.S..^[91] The CIA, as revealed by declassified documents, was deeply involved in the planning and execution of the coup, including hiring mobs to incite pro-Shah riots.^[84] The conflict resulted in 200 to 300 deaths, and Mosaddegh was arrested, tried for treason, and sentenced to house arrest for life.^[92]

The Shah continued his rule for another 26 years until the Iranian Revolution in 1979. In 2013, the U.S. government formally acknowledged its role in the coup with the release of classified documents, revealing the extent of its involvement and planning. In 2023, the CIA admitted that backing the coup was "undemocratic," highlighting the significant impact of this event on Iran's political history and U.S.-Iran relations.^[93]