The Mikoyan MiG-31 (Russian: Микоян МиГ-31; NATO reporting name: Foxhound) is a supersonic interceptor aircraft developed for the Soviet Air Forces by the Mikoyan design bureau as a replacement for the MiG-25 "Foxbat", on which it is based and shares design elements.

The MiG-31 is the fastest known operational combat aircraft, with a top speed around 3,000 km/h (1,600 knots). It continues to be operated by the Russian Aerospace Forces following the end of the Cold War and the collapse of the Soviet Union in 1991. The other operator, the Kazakh Air Defence Forces, retired the type in 2023. The Russian Defence Ministry expects the MiG-31 to remain in service until at least 2030; that was confirmed in 2020 when an announcement was made to extend the service lifetime of the existing airframes from 2,500 to 3,500 hours. The MiG-31K variant carries the Kh-47M2 Kinzhal conventional or nuclear warhead-capable air-launched ballistic missile.