The Boeing 757 is a mid-size, narrow-body twin-engine jet airliner that was built by Boeing Commercial Airplanes from 1981 to 2004. It is the manufacturer's largest single-aisle passenger aircraft. The twinjet has a two-crewmember glass cockpit, turbofan engines, a conventional tail and, for reduced aerodynamic drag, a supercritical wing design. Intended to replace the smaller three-engine Boeing 727 on short and medium routes, the 757 can carry 200 to 289 passengers for a maximum of 3,150 to 4,100 nautical miles, depending on the variant. The 757 was designed concurrently with a wide-body twinjet, the Boeing 767, and owing to shared features pilots can obtain a common type rating that allows them to operate both aircraft.

Production of the 757 ended on October 28, 2004, after 1,050 had been built for 54 customers. The 757-200 was by far the most popular model, with 913 built. Diminished sales  amid an airline industry trend toward smaller jetliners led Boeing to end production without a direct replacement, in favour of the Boeing 737 family. The last 757 was delivered to Shanghai Airlines on November 28, 2005. In 2011, 898 of the narrow-body twinjets were in airline service, and Delta Air Lines was the largest operator, with 185 aircraft

The landing gear was purposely designed to be taller than the  company's previous narrow-body aircraft in order to provide ground  clearance for the longer, stretched models. In 1982, the 757-200 became the first subsonic jetliner to offer carbon brakes as a factory option, supplied by Dunlop (Concorde was the world’s first civil airliner to use a carbon braking system). The stretched 757-300 features a retractable tailskid on its aft fuselage to prevent damage if the tail section contacts the runway surface during takeoff.

Besides common avionics and computer systems, the 757 shares its auxiliary power unit, electric power systems, flight deck, and hydraulic parts with the Boeing 767. Through operational commonality, 757 pilots can obtain a common type rating to fly the 767 and share the same seniority roster with pilots of either aircraft. This reduces costs for airlines that operate both twinjets.