The McDonnell Douglas YC-15 was a wide-body transport aircraft for service on short, undeveloped airfields. Two McDonnell Douglas YC-15 prototypes were built for the Air Force's advanced medium STOL transport (AMST) program.

YC-15 featured a supercritical wing and externally blown flaps to increase low speed lift. Although production was never approved, many of the technologies demonstrated on the YC-15 were incorporated into the C-17 aircraft, including the short-field landing capability.

The two YC-15s completed a 600 hour flight test program in 1977. One YC-15 resumed flying in April 1997 to evaluate new technology for advanced tactical transports. After an engine failed, the aircraft was deemed too expensive to repair and was returned to storage.