The Sukhoi Su-57 (Russian: Сухой Су-57; NATO reporting name: Felon)^[5] is a twin-engine stealth multirole fighter aircraft developed by Sukhoi.^[6] It is the product of the PAK FA (Russian: ПАК ФА, short for: Перспективный авиационный комплекс фронтовой авиации, romanized: Perspektivnyy Aviatsionnyy Kompleks Frontovoy Aviatsii, lit. ''prospective aeronautical complex of front-line air forces'') programme, which was initiated in 1999 as a more modern and affordable alternative to the MFI (Mikoyan Project 1.44/1.42). Sukhoi's internal designation for the aircraft is T-50. The Su-57 is the first aircraft in Russian military service designed with stealth technology and is intended to be the basis for a family of stealth combat aircraft.

A multirole fighter capable of aerial combat as well as ground and maritime strike, the Su-57 incorporates stealth, supermaneuverability, supercruise, integrated avionics, and substantial internal payload capacity.^[7] The aircraft is expected to succeed the MiG-29 and Su-27 in the Russian military service and has also been marketed for export. The first prototype aircraft flew in 2010, and after a protracted development due to various issues that emerged during trials, including the destruction of the first production aircraft in a crash before its delivery, the first Su-57 entered service with the Russian Aerospace Forces (VKS)^{[N 2]} in December 2020.^[8] The fighter is expected to have a service life of up to 35 years.^[9]