Iran–United States relations

Relations between Iran and the United States in modern day are unsettled and have a troubled history. They began in the mid-to-late 19th century, when Iran was known to the Western world as Qajar Persia. Persia was very wary of British and Russian colonial interests during the Great Game. By contrast, the United States was seen as a more trustworthy foreign power, and the Americans Arthur Millspaugh and Morgan Shuster were even appointed treasurers-general by the Shahs of the time. During World War II, Iran was invaded by the United Kingdom and the Soviet Union, both US allies, but relations continued to be positive after the war until the later years of the government of Mohammad Mosaddegh, who was overthrown by a coup organized by the Central Intelligence Agency and aided by MI6. This was followed by an era of close alliance between Shah Mohammad Reza Pahlavi's authoritarian regime and the US government, Iran being one of the US's closest allies during the Cold War, which was in turn followed by a dramatic reversal and disagreement between the two countries after the 1979 Iranian Revolution.

The two nations have had no formal diplomatic relations since April 7, 1980. Instead, Pakistan serves as Iran's protecting power in the United States, while Switzerland serves as the United States' protecting power in Iran. Contacts are carried out through the Iranian Interests Section of the Pakistani Embassy in Washington, D.C., and the US Interests Section of the Swiss Embassy in Tehran. In August 2018, Supreme Leader of Iran Ali Khamenei banned direct talks with the United States. According to the US Department of Justice, Iran has since attempted to assassinate US officials and dissidents, including US president Donald Trump.

Iranian explanations for the animosity with the United States include "the natural and unavoidable conflict between the Islamic system" and "such an oppressive power as the United States, which is trying to establish a global dictatorship and further its own interests by dominating other nations and trampling on their rights", as well as the United States support for Israel ("the Zionist entity"). In the West, however, various explanations have been considered, including the Iranian government's need for an external bogeyman to furnish a pretext for domestic repression against pro-democratic forces and to bind the government to its loyal constituency. The United States attributes the worsening of relations to the 1979–81 Iran hostage crisis, Iran's repeated human rights abuses since the Islamic Revolution, different restrictions on using spy methods on democratic revolutions by the US, its anti-Western ideology, its nuclear program, and political, financial, and military support to armed groups committed primarily to countering the influence of US and Israel in the West Asia.

Since 1995, the United States has had an embargo on trade with Iran. In 2015, the United States led successful negotiations for a nuclear deal (the Joint Comprehensive Plan of Action) intended to place substantial limits on Iran's nuclear program, including IAEA inspections and limitations on enrichment levels. In 2016, most sanctions against Iran were lifted. The Trump administration unilaterally withdrew from the nuclear deal and re-imposed sanctions in 2018, initiating what became known as the "maximum pressure campaign" against Iran. In response, Iran gradually reduced its commitments under the nuclear deal and eventually exceeded pre-JCPOA enrichment levels. The Biden administration did not relax the economic sanctions against Iran, and instead implemented more measures. The second Trump administration reimposed the "maximum pressure" approach on Iran.

According to a 2013 BBC World Service poll, 5% of Americans view Iranian influence positively, with 87% expressing a negative view, the most unfavorable perception of Iran in the world. On the other hand, research has shown that most Iranians hold a positive attitude about the American people, though not the US government. According to a 2019 survey by IranPoll, 13% of Iranians have a favorable view of the United States, with 86% expressing an unfavourable view, the most unfavorable perception of the United States in the world. According to a 2018 Pew poll, 39% of Americans say that limiting the power and influence of Iran should be a top foreign policy priority. Relations tend to improve when the two countries have overlapping goals, such as repelling Sunni militants during the Iraq War and the intervention against the Islamic State in the region.

On 28 February 2026, Israel and the United States launched a joint attack on various sites in Iran. The operation, codenamed Roaring Lion by Israel and Operation Epic Fury by the United States Department of Defense, targeted key officials, military commanders, facilities and was aimed at regime change. The attack included the assassination of Iranian supreme leader Ali Khamenei.