The 103d Fighter Squadron (103 FS) is an inactive unit of the Pennsylvania Air National Guard. It was last assigned to the 111th Fighter Wing, stationed at Naval Air Station Joint Reserve Base Willow Grove, Willow Grove, Pennsylvania. The squadron was inactivated on 31 March 2011. The squadron was a descendant organization of the Pennsylvania National Guard 103d Observation Squadron, formed on 27 June 1924. It was one of the 29 original National Guard Observation Squadrons of the United States Army National Guard formed before World War II.