The Sukhoi Su-27 (Russian: ????? ??-27; NATO reporting name: Flanker) is a Soviet-origin twin-engine supersonic supermaneuverable fighter aircraft designed by Sukhoi. It was intended as a direct competitor for the large US fourth-generation jet fighters such as the Grumman F-14 Tomcat and McDonnell Douglas F-15 Eagle, with 3,530-kilometre (1,910 nmi) range, heavy aircraft ordnance, sophisticated avionics and high maneuverability. The Su-27 was designed for air superiority missions, and subsequent variants are able to perform almost all aerial warfare operations. It was designed with the Mikoyan MiG-29 as its complement.

The Su-27 entered service with the Soviet Air Forces in 1985. The primary role was long range air defence against American SAC Rockwell B-1B Lancer and Boeing B-52G and H Stratofortress bombers, protecting the Soviet coast from aircraft carriers and flying long range fighter escort for Soviet heavy bombers such as the Tupolev Tu-95, Tupolev Tu-22M and Tupolev Tu-160.[2]

The Su-27 was developed into a family of aircraft; these include the Su-30, a two-seat, dual-role fighter for all-weather, air-to-air and air-to-surface deep interdiction missions, and the Su-33, a naval fleet defense interceptor for use from aircraft carriers. Further versions include the side-by-side two-seat Su-34 strike/fighter-bomber variant, and the Su-35 improved air superiority and multi-role fighter. A thrust-vectoring version was created, called the Su-37. The Shenyang J-11 is a Chinese license-built version of the Su-27.