The 504th Expeditionary Air Support Operations Group is an inactive United States Air Force unit. It was first activated as the 504th Tactical Air Support Group in 1966 for service during the Vietnam War, and was reactivated in 2009 for service in Afghanistan. It was inactivated on 12 May 2016. On reactivation in 2009 it began to provide air support, air liaison, and weather support for ground operations until it was inactivated on 12 May 2016.