The Iraq War, sometimes called the Second Persian Gulf War was a protracted armed conflict in Iraq from 2003 to 2011. It began with the invasion of Iraq by the United States-led coalition that overthrew the Ba'athist government of Saddam Hussein. The conflict continued for much of the next decade as an insurgency emerged to oppose the coalition forces and the post-invasion Iraqi government. US troops were officially withdrawn in 2011.

The United States-led invasion of the Republic of Iraq was the first stage of the Iraq War. The invasion began on 19 March 2003 and lasted just over one month, including 26 days of major combat operations, in which a combined force of troops from the United States, the United Kingdom, Australia and Poland invaded Iraq. Twenty-two days after the first day of the invasion, the capital city of Baghdad was captured by coalition forces on 9 April after the six-day-long Battle of Baghdad. This early stage of the war formally ended on 1 May when U.S. President George W. Bush declared the "end of major combat operations" in his Mission Accomplished speech, after which the Coalition Provisional Authority (CPA) was established as the first of several successive transitional governments leading up to the first Iraqi parliamentary election in January 2005. U.S. military forces later remained in Iraq until the withdrawal in 2011.