1953 Iranian coup d'état

The 1953 Iranian coup d'état, known in Iran as the 28 Mordad coup d'état (Persian: کودتای ۲۸ مرداد), was the U.S.- and British-instigated, Iranian army-led overthrow of the elected Prime Minister Mohammad Mosaddegh in favor of strengthening the monarchical rule of the shah, Mohammad Reza Pahlavi, on 19 August 1953, with one of the significant objectives being to protect British oil interests in Iran. It was aided by the United States (under the name TP-AJAX (Tudeh Party) Project or Operation Ajax) and the United Kingdom (under the name Operation Boot).

Mosaddegh had sought to audit the documents of the Anglo-Iranian Oil Company (AIOC), a British corporation (now part of BP), to verify that AIOC was paying the contracted royalties to Iran, and to limit the company's control over Iranian oil reserves. Upon the AIOC's refusal to cooperate with the Iranian government, the parliament (Majlis) voted to nationalize Iran's oil industry and to expel foreign corporate representatives from the country. After this vote, Britain instigated a worldwide boycott of Iranian oil to pressure Iran economically. Initially, Britain mobilized its military to seize control of the British-built Abadan oil refinery, then the world's largest, but Prime Minister Clement Attlee (in power until 1951) opted instead to tighten the economic boycott while using Iranian agents to undermine Mosaddegh's government.^: 3 Judging Mosaddegh to be unamenable and fearing the growing influence of the communist Tudeh, UK prime minister Winston Churchill and the Eisenhower administration decided in early 1953 to overthrow Iran's government. The preceding Truman administration had opposed a coup, fearing the precedent that Central Intelligence Agency (CIA) involvement would set,^: 3 and the U.S. government had been considering unilateral action (without UK support) to assist the Mosaddegh government as late as 1952. British intelligence officials' conclusions and the UK government's solicitations to the US were instrumental in initiating and planning the coup.

Following the coup, a government under General Fazlollah Zahedi was formed which allowed Mohammad Reza Pahlavi, the shah of Iran (Persian for 'king'), to rule more firmly as monarch. He relied heavily on United States support to hold on to power. According to the CIA's declassified documents and records, some of the most feared mobsters in Tehran were hired by the CIA to stage pro-shah riots on 19 August. Other men paid by the CIA were brought into Tehran in buses and trucks and took over the streets of the city. Between 200 and 300 people were killed because of the conflict. Mosaddegh was arrested, tried and convicted of treason by the Shah's military court. On 21 December 1953, he was sentenced to three years in jail, then placed under house arrest for the remainder of his life.^: 280 Other Mosaddegh supporters were imprisoned, and several received the death penalty. The coup resulted in the reinstatement of the Shah's authority, and he continued to rule Iran for the next 26 years as a pro-Western monarch until he was overthrown in the Iranian Revolution in 1979.

In August 2013, the U.S. government formally acknowledged the U.S. role in the coup by releasing a bulk of previously classified government documents that show it was in charge of both the planning and the execution of the coup. According to American journalist Stephen Kinzer, the operation included false flag attacks, paid protesters, provocations, the bribing of Iranian politicians and high-ranking security and army officials, as well as pro-coup propaganda. The CIA is quoted acknowledging the coup was carried out "under CIA direction" and "as an act of U.S. foreign policy, conceived and approved at the highest levels of government". In 2023, the CIA took credit for the coup, contradicted by previous scholarly assessment that the CIA had botched the operation.