The 66th Troop Carrier Squadron is an inactive unit of the United States Air Force. Its last assignment was with the 403d Troop Carrier Group, stationed at Portland Municipal Airport, Oregon.
It was inactivated on 17 April 1951.
During World War II, the squadron operated primarily in the Southwest Pacific Theater, conveying personnel, dropping parachutists, towing gliders, transporting cargo, munitions and evacuating casualties in numerous campaigns. The squadron earned both the United States Distinguished Unit Citation and the Philippine Presidential Unit Citation for its combat operations.
As part of the Air Force Reserve during the postwar years, the squadron performed peacetime transport missions. Ordered to active service during the Korean War, the units' equipment and personnel were reassigned to Far East Air Force active duty units.
It was then inactivated as a paper unit.