After a seven-hour debate, MPs voted for military action by 524 votes to 43.
The Conservatives, Lib Dems and Labour leaderships all backed air strikes although some MPs expressed concerns about where it would lead and the prospect of future engagement in Syria.
The BBC's political editor Nick Robinson said RAF planes could be called into action as early as Sunday.
Speaking after the vote, Defence Secretary Michael Fallon said a long campaign lay ahead and there would not be a "series of immediate hits".
He told the BBC the priority would be to stop the "slaughter of civilians" in Iraq and the UK and its allies would continue to be guided by Iraqi and Kurdish intelligence in identifying targets.