Iran and Israel have had no diplomatic relations since 1979, and modern relations are hostile. The relationship was cordial for most of the Cold War, but worsened following the Iranian Revolution and has been openly hostile since the end of the Gulf War in 1991. Iran's current government does not recognize Israel's legitimacy as a state and has called for its destruction; it views Palestine as the sole legitimate government of the historic Palestinian territories. Israel considers Iran a threat to the Middle East's stability and has targeted Iranian assets in assassinations and airstrikes. In 2025, the hostility escalated to an armed conflict.

In 1947, Iran was among 13 countries that voted against the United Nations Partition Plan for the British Mandate of Palestine. Two years later, Iran also voted against Israel's admission to the United Nations. However, Iran was the second Muslim-majority country to recognize Israel as a sovereign state after Turkey. After the 1953 coup d'état, which reinstalled the pro-Western leader Mohammad Reza Pahlavi as the shah of Iran, relations between the two countries significantly improved. After the Iranian revolution—in which Pahlavi was ousted and Iran's secular monarchy was replaced by an anti-Western Islamic republic—Iran severed diplomatic and commercial ties with Israel, although relations continued covertly during the Iran–Iraq War (1980–1988).

Since 1985, Iran and Israel have been engaged in a proxy conflict that has greatly affected the geopolitics of the Middle East. The turn from cold peace to open hostility began in the early 1990s, shortly after the collapse of the Soviet Union and the defeat of Iraq in the Gulf War. Israeli prime minister Yitzhak Rabin's government adopted a more aggressive posture on Iran, and Iranian president Mahmoud Ahmadinejad made inflammatory statements against Israel. Other factors contributing to the escalation of tensions include the Iranian nuclear program, Iran's funding of Islamist groups such as Hezbollah, Palestinian Islamic Jihad, Hamas, and the Houthis, and Iran's involvement in attacks such as the 1992 Buenos Aires Israeli embassy bombing and the 1994 AMIA bombing, as well as Israeli threats of military action.

Iranian and Israeli organizations have been involved in direct military confrontations, such as in the 2006 Lebanon War. Iran and Israel have provided support for opposing factions in the Syrian and Yemeni civil wars and conducted cyberattacks and sabotage against each other's infrastructure, including attacks on nuclear facilities and oil tankers. Iran's proxy conflict with Saudi Arabia has led to an informal alliance between Israel and Arab states. In 2024, amid increasing regional tensions stemming from the Gaza war, Iran–Israel tensions escalated to a period of direct conflict; both carried out missile strikes on the other and Israel assassinated targets in Iran and Syria. In 2025, Israel carried out strikes against Iranian nuclear and military targets, sparking the 12 day long Iran–Israel war.

The beginnings of Jewish history in Iran dates from late Biblical times. The biblical books of Isaiah, Daniel, Ezra, Nehemiah, Chronicles, and Esther contain references to the life and experiences of Jews in Persia. In the book of Ezra, the Persian king Cyrus the Great is credited with permitting and enabling the Jews to return to Jerusalem and rebuild their Temple; its reconstruction was carried out "according to the decree of Cyrus, and Darius, and Artaxerxes king of Persia" (Ezra 6:14). This is said to have taken place in the late sixth century BC, by which time there was a well-established and influential Jewish community in Persia. Persian Jews have lived in the territories of today's Iran for over 2,700 years, since the first Jewish diaspora when Shalmaneser V conquered the (Northern) Kingdom of Israel (722 BC) and sent the Israelites into captivity at Khorasan. In 586 BC, the Babylonians expelled large populations of Jews from Judea to the Babylonian captivity. Jews who migrated to ancient Persia mostly lived in their own communities.

The Jewish Bible's Ketuvim ends in Second Chronicles with the decree of Cyrus, which returned the exiles to the Promised Land from Babylon along with a commission to rebuild the temple.

'Thus saith Cyrus, king of Persia: All the kingdoms of the earth hath Yahweh, the God of heaven, given me; and He hath charged me to build Him a house in Jerusalem, which is in Judah. Whosoever there is among you of all His people—may Yahweh, his God, be with him—let him go there.' (2 Chronicles 36:23)

This edict is also fully reproduced in the Book of Ezra.