The Iran hostage crisis () began on November 4, 1979, when 66 Americans, including diplomats and other civilian personnel, were taken hostage at the Embassy of the United States in Tehran, with 52 of them being held until January 20, 1981. The incident occurred after the Muslim Student Followers of the Imam's Line stormed and occupied the building in the months following the Iranian Revolution. With support from Ruhollah Khomeini, who had led the Iranian Revolution and would eventually establish the present-day Islamic Republic of Iran, the hostage-takers demanded that the United States extradite Iranian king Mohammad Reza Pahlavi, who had been granted asylum by the Carter administration for cancer treatment. Notable among the assailants were Hossein Dehghan (future Minister of Defense of Iran), Mohammad Ali Jafari (future Commander-in-Chief of the Islamic Revolutionary Guard Corps), and Mohammad Bagheri (future Chief of the General Staff of the Iranian Armed Forces). The hostage crisis contributed to a dramatic decline in Iran–United States relations. After 444 days, it came to an end with the signing of the Algiers Accords between the Iranian and American governments; Pahlavi had died in Cairo, Egypt, on July 27, 1980.

The American magazine Time described the Iran hostage crisis as an entanglement of vengeance and mutual incomprehension. American president Jimmy Carter called the hostage-taking an act of "blackmail" and the hostages "victims of terrorism and anarchy." Among proponents of the Iranian Revolution, it was seen as an act against perceived attempts by the United States to undermine the uprising against Iran's king, who had been accused of committing numerous human rights abuses against Iranian dissidents through his Bureau for Intelligence and Security of the State. The Carter administration's refusal to extradite Pahlavi was cited by the hostage-takers as proof of complicity on the part of the United States, which, in turn, denounced the Iranians' hostage-taking as an egregious violation of the principles of international law, such as the Vienna Convention, under which diplomats and diplomatic compounds are to be granted immunity from coercion and harassment.Kinzer, Stephen (2003). All The Shah's Men: An American Coup and the Roots of Middle East Terror. Hoboken, New Jersey: John Wiley & Sons.

Six American diplomats who had evaded capture were rescued by the "Canadian Caper" on January 27, 1980. As Iran hostage crisis negotiations dragged out and did not secure the release of the remaining hostages, Carter approved Operation Eagle Claw on April 24, 1980. The effort failed, however, resulting in the death of one Iranian civilian and eight American soldiers, prompting Secretary of State Cyrus Vance to resign from his position. By September 1980, the beginning of the Iraqi invasion of Iran spurred the Iranian government to negotiate with the United States as part of an initiative mediated by Algeria.

Political analysts cited the standoff as a major factor in the downfall of Carter's presidency, culminating in his landslide loss in the 1980 presidential election."Reagan's Lucky Day: Iranian Hostage Crisis Helped The Great Communicator To Victory". CBS News. January 21, 2001. The hostages were formally released into American custody one day after the Algiers Accords were signed, just minutes following the first inauguration of Ronald Reagan. In Iran, the crisis strengthened the prestige of Khomeini and the political power of theocrats who opposed normalization with the Western world.Mackey, Sandra (1996). The Iranians: Persia, Islam and the Soul of a Nation. New York: Dutton. p. 298. Since then, the United States has enforced international sanctions against Iran with regard to the latter's nuclear ambitions and human rights record, further weakening ties between the two countries.

Background 1953 Iranian coup d'état

During the Second World War, the British and the Soviet governments invaded and occupied Iran, forcing the first Pahlavi monarch, Reza Shah Pahlavi, to abdicate in favor of his eldest son, Mohammad Reza Pahlavi.Abrahamian, Iran Between Two Revolutions, (1982), p. 164 The two nations claimed that they acted pre-emptively in order to stop Reza Shah from aligning his petroleum-rich country with Nazi Germany. However, the Shah's declaration of neutrality, and his refusal to allow Iranian territory to be used to train or supply Soviet troops, were probably the real reasons for the invasion of Iran.

The United States did not participate in the invasion but it secured Iran's independence after the war ended by applying intense diplomatic pressure on the Soviet Union which forced it to withdraw from Iran in 1946.

By the 1950s, Mohammad Reza Pahlavi was engaged in a power struggle with Iran's prime minister, Mohammad Mosaddegh, an immediate descendant of the preceding Qajar dynasty. Mosaddegh led a general strike, demanding an increased share of the nation's petroleum revenue from the Anglo-Iranian Oil Company which was operating in Iran. The UK retaliated by reducing the amount of revenue which the Iranian government received. In 1953, the CIA and MI6 helped Iranian royalists depose Mosaddegh in a military coup d'état codenamed Operation Ajax, allowing the Shah to extend his power. For the next two decades the Shah reigned as an absolute monarch. "Disloyal" elements within the state were purged.Amjad, Mohammed (1989). Iran: From Royal Dictatorship to Theocracy. Greenwood Press. . p. 62: "the United States had decided to save the 'free world' by overthrowing the democratically elected government of Mosaddegh." The U.S. continued to support the Shah after the coup, with the CIA training the Iranian secret police. In the subsequent decades of the Cold War, various economic, cultural, and political issues united Iranian opposition against the Shah and led to his eventual overthrow.

The Carter administration and the Shah Months before the Iranian Revolution, on New Year's Eve 1977, U.S. President Jimmy Carter further angered anti-Shah Iranians with a televised toast to Pahlavi at a state dinner in Tehran, saluting the Shah's character.Bowden, pp. 115–116 After the revolution commenced in February 1979 with the return of the Ayatollah Khomeini from exile, the American Embassy was occupied, and its staff held hostage briefly. Rocks and bullets had broken so many of the embassy's front-facing windows that they were replaced with bulletproof glass. The embassy's staff was reduced to just over 60 from a high of nearly one thousand earlier in the decade.Bowden, p. 19

The Carter administration tried to mitigate anti-American feeling by promoting a new relationship with the de facto Iranian government and continuing military cooperation in the hope that the situation would stabilize. However, on October 22, 1979, the United States permitted the Shah, who had lymphoma, to enter New York Hospital-Cornell Medical Center for medical treatment. The State Department had discouraged this decision, understanding the political delicacy. But in response to pressure from influential figures including former Secretary of State Henry Kissinger and Council on Foreign Relations Chairman David Rockefeller, the Carter administration decided to grant it.Farber, p. 122Kirkpatrick, David D. (December 29, 2019) How a Chase Bank Chairman Helped . New York Times. The activities of the Chase Manhattan Bank triggered the whole hostages crisis.

The Shah's admission to the United States intensified Iranian revolutionaries' anti-Americanism and spawned rumors of another U.S.–backed coup that would re-install him. Khomeini, who had been exiled by the Shah for 15 years, heightened the rhetoric against the "Great Satan", as he called the U.S., talking of "evidence of American plotting."Moin, p. 220 In addition to ending what they believed was American sabotage of the revolution, the hostage takers hoped to depose the provisional revolutionary government of Prime Minister Mehdi Bazargan, which they believed was plotting to normalize relations with the U.S. and extinguish Islamic revolutionary order in Iran.Bowden, p. 10 The occupation of the embassy on November 4, 1979, was also intended as leverage to demand the return of the Shah to stand trial in Iran in exchange for the hostages.

Prelude First embassy assault

On the morning of February 14, 1979, the Organization of Iranian People's Fedai Guerrillas stormed the U.S. Embassy in Tehran and took a Marine named Kenneth Kraus hostage. Ambassador William H. Sullivan surrendered the embassy to save lives, and with the assistance of Iranian Foreign Minister Ebrahim Yazdi, returned the embassy to U.S. hands within three hours. Kraus was injured in the attack, kidnapped by the militants, tortured, tried, and convicted of murder. He was to be executed, but President Carter and Sullivan secured his release within six days. This incident became known as the Valentine's Day Open House.

Second embassy assault The next attempt to seize the American Embassy was planned for September 1979 by Ebrahim Asgharzadeh, a student at the time. He consulted with the heads of the Islamic associations of Tehran's main universities, including the University of Tehran, Sharif University of Technology, Amirkabir University of Technology (Polytechnic of Tehran), and Iran University of Science and Technology. They named their group Muslim Student Followers of the Imam's Line.

Asgharzadeh later said there were five students at the first meeting, two of whom wanted to target the Soviet Embassy because the USSR was "a Marxist and anti-God regime". Two others, Mohsen Mirdamadi and Habibolah Bitaraf, supported Asgharzadeh's chosen target, the United States. "Our aim was to object against the American government by going to their embassy and occupying it for several hours," Asgharzadeh said. "Announcing our objections from within the occupied compound would carry our message to the world in a much more firm and effective way." Mirdamadi told an interviewer, "We intended to detain the diplomats for a few days, maybe one week, but no more."Molavi, Afshin (2005) The Soul of Iran, Norton. p. 335. Masoumeh Ebtekar, the spokeswoman for the Iranian students during the crisis, said that those who rejected Asgharzadeh's plan did not participate in the subsequent events.

The students observed the procedures of the Marine Security Guards from nearby rooftops overlooking the embassy. They also drew on their experiences from the recent revolution, during which the U.S. Embassy grounds were briefly occupied. They enlisted the support of police officers in charge of guarding the embassy and of the Islamic Revolutionary Guards.Bowden, pp. 8, 13

Asgharzadeh and other senior organizers (including Abbas Abdi and Mohsen Mirdammadi, now a professor of political science) rejected claims that Ayatollah Ruhollah Khomeini had orchestrated or instructed them to carry out the attack. The students had wanted to inform him, but according to the author Mark Bowden, Ayatollah Mohammad Mousavi Khoeiniha persuaded them not to do so. Khoeiniha feared that the government would use the police to expel the students as they had the occupiers in February. The provisional government had been appointed by Khomeini, so Khomeini was likely to go along with the government's request to restore order. On the other hand, Khoeiniha knew that if Khomeini first saw that the occupiers were faithful supporters of him (unlike the leftists in the first occupation) and that large numbers of pious Muslims had gathered outside the embassy to show their support for the takeover, it would be "very hard, perhaps even impossible," for him to oppose the takeover, and this would paralyze the Bazargan administration, which Khoeiniha and the students wanted to eliminate.Bowden, p. 12

Supporters of the takeover stated that their motivation was fear of another American-backed coup against their popular revolution.