In 1966 the United States Air Force (USAF) commissioned Cessna to build a military variant of the Skymaster.
As with the civilian version, the Skymaster was a low-cost twin-engine piston-powered aircraft, with one engine in the nose of the aircraft and a second engine in the rear of the fuselage.
The USAF took delivery of the O-2 Skymaster in March 1967. By 1970, a total of 532 O-2s had been built, in two variants, for the USAF.
During the Vietnam War, the O-2A was introduced as the forward air control (FAC) aircraft.