The Yakovlev Yak-9 is a single-engine, single-seat multipurpose fighter aircraft used by the Soviet Union and its allies during World War II and the early Cold War. It was a development of the robust and successful Yak-7B fighter, which was based in turn on the tandem-seat advanced trainer known as the Yak-7UTI. The Yak-9 started arriving in Soviet fighter regiments in late 1942 and played a major role in retaking air superiority from the Luftwaffe's new Focke-Wulf Fw 190 and Messerschmitt Bf 109G fighters during the grand Battle of Kursk in summer 1943.

Fighter aircraft are military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air superiority of the battlespace. Domination of the airspace above a battlefield permits bombers and attack aircraft to engage in tactical and strategic bombing of enemy targets.