- April 1, 1979 - Iran's government becomes an Islamic Republic by a 98% vote, overthrowing the Shah officially.
- April 18, 2005 - Five people die in ethnic clashes in Iran's south-west Khuzestan province.
- April 20, 1925 - Iranian forces of Rezā Shāh occupy Ahwaz, and arrest Sheikh Khaz'al.
- April 24–April 25, 1980 – Operation Eagle Claw, a commando mission in Iran to rescue American embassy hostages, is aborted after mechanical problems ground the rescue helicopters. Eight United States troops are killed in a mid-air collision during the failed operation.