The First Battle of Khorramshahr was a major battle in the Iran–Iraq War, beginning shortly after the Iraqi invasion of Iran in September 1980. Amidst the gruelling urban warfare in and around the city, Khorramshahr came to be referred to by the Iranians as Khuninshahr, as both sides had suffered heavy casualties in combat. It was the single largest urban battle of the Iran–Iraq war.

The Iran–Iraq War, also known as the First Gulf War, was an armed conflict between Iran and Iraq that lasted from September 1980 to August 1988. Active hostilities began with the Iraqi invasion of Iran and lasted for eight years, until the acceptance of United Nations Security Council Resolution 598 by both sides. Iraq's primary rationale for the attack against Iran cited the need to prevent Ruhollah Khomeini—who had spearheaded the Iranian Revolution in 1979—from exporting the new Iranian ideology to Iraq. There were also fears among the Iraqi leadership of Saddam Hussein that Iran, a theocratic state with a population predominantly composed of Shia Muslims, would exploit sectarian tensions in Iraq by rallying Iraq's Shia majority against the Baʽathist government, which was officially secular and dominated by Sunni Muslims. Iraq also wished to replace Iran as the power player in the Persian Gulf, which was not seen as an achievable objective prior to the Islamic Revolution because of Pahlavi Iran's economic and military superiority as well as its close relationships with the United States and Israel.