"Article 5 has been invoked only once in NATO history, after the September 11 attacks on the United States in 2001.[58][59] The invocation was confirmed on 4 October 2001, when NATO determined that the attacks were indeed eligible under the terms of the North Atlantic Treaty.[60] The eight official actions taken by NATO in response to the 9/11 attacks included Operation Eagle Assist and Operation Active Endeavour, a naval operation in the Mediterranean which was designed to prevent the movement of terrorists or weapons of mass destruction, as well as enhancing the security of shipping in general. Active Endeavour began on 4 October 2001.[61]"

They seemingly didn't decide that it was required to fight alongside us in Afghanistan (though many NATO allies did), but they did treat 9/11 as an attack for NATO purposes. Ukraine is different in that they're not in NATO, while the first Gulf War didn't involve an attack on a NATO member.