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United States–Iran Relations

United States–Iran relations refer to the diplomatic, political, and strategic relationship between the two countries.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 26, 2026|2 min read| Fact-checked

United States–Iran relations refer to the diplomatic, political, and strategic relationship between the two countries. The relationship shifted from close cooperation during the Pahlavi era to open hostility after the 1979 Iranian Revolution and the Iran hostage crisis, and formal diplomatic ties have been absent since 1980.

Historical background

The relationship developed gradually from the 19th century, but became much more important during the Cold War and the era of oil politics. A period of close U.S.–Iran cooperation under the Shah was followed by a sharp deterioration after the 1979 Iranian Revolution.

Breakdown of relations

The Iran hostage crisis was a decisive event in the rupture between the two countries. After the crisis, formal diplomatic relations were severed and have remained suspended.

Major issues in the relationship

Key sources of tension include sanctions, Iran’s nuclear programme, regional conflicts, and mutual accusations of destabilising behaviour. The relationship is also influenced by broader competition in the Middle East.

Diplomatic channels and mediation

Because the two states do not have normal diplomatic relations, communication has often taken place through intermediaries. Switzerland represents U.S. interests in Iran, while Pakistan has represented Iranian interests in the United States.

Key facts

  • Relations began in the 19th century but became geopolitically significant in the 20th.
  • The two countries were allies during much of the reign of Mohammad Reza Pahlavi.
  • The 1979 Iranian Revolution and the hostage crisis led to the breakdown of relations.
  • The United States and Iran have had no formal diplomatic relations since 1980.
  • The relationship has been shaped by sanctions, regional rivalry, and disputes over Iran’s nuclear programme.
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Canadian context

Canadian readers may encounter this relationship in coverage of Middle East security, sanctions policy, nuclear non-proliferation, and global energy markets, all of which can affect Canada’s foreign policy and economy.

Frequently asked questions

When did United States–Iran relations begin to deteriorate?
The modern breakdown began after the 1979 Iranian Revolution and the 1979–1981 hostage crisis, which ended formal diplomatic relations.
Do the United States and Iran have embassies in each other’s capitals?
No. They do not have formal diplomatic relations, and their interests are handled through third countries.
What is the main source of tension between the two countries?
Major tensions include Iran’s nuclear programme, sanctions, regional security disputes, and long-standing mutual distrust.
Were the United States and Iran ever allies?
Yes. They had a period of close alignment during the rule of Mohammad Reza Pahlavi, especially in the Cold War era.
Who represents U.S. interests in Iran?
Switzerland has traditionally represented U.S. interests in Iran.
Who represents Iranian interests in the United States?
Pakistan has represented Iranian interests in the United States.

References

  1. BBC News Mundo — https://www.bbc.com/mundo/noticias-internacional-48759280
    Supports: The 1979 crisis and the break in diplomatic relations.
  2. SWI swissinfo.ch — https://www.swissinfo.ch/spa/estados-unidos-e-ir%C3%A1n,-una-relaci%C3%B3n-turbulenta/89560706
    Supports: Rupture of diplomatic relations, nuclear deal history, and Switzerland representing U.S. interests.
  3. El Economista — https://www.eleconomista.com.mx/internacionales/recorrido-larga-tortuosa-relacion-ee-uu-e-iran-20250627-765720.html
    Supports: Hostility since the 1979 hostage crisis and post-1984 U.S. designation of Iran as a state sponsor of terrorism.
  4. The Conversation — https://www.theconversation.com/un-recorrido-por-la-larga-y-tortuosa-relacion-entre-ee-uu-e-iran-259550
    Supports: Historical roots in the 1953 coup and support for the Shah.
  5. BBC News Mundo — https://www.bbc.com/mundo/articles/clyxd3gqrqxo
    Supports: Broad historical evolution from close ties to hostility.
  6. Wikipedia — https://es.wikipedia.org/wiki/Relaciones_Estados_Unidos-Ir%C3%A1n
    Supports: General overview, lack of formal diplomatic relations, and intermediary representation.