The Boeing 757 is a mid-size, narrow-body twin-engine jet airliner that was designed and built by Boeing Commercial Airplanes. It is the manufacturer’s largest single-aisle passenger aircraft and was produced from 1981 to 2004. The twinjet has a two-crew member glass cockpit, turbofan engines of sufficient power to allow takeoffs from relatively short runways and higher altitudes, a conventional tail and, for reduced aerodynamic drag, a supercritical wing design. Intended to replace the smaller three-engine 727 on short and medium routes, the 757 can carry 200 to 295 passengers for a maximum of 3,150 to 4,100 nautical miles (5,830 to 7,590 km), depending on variant. The 757 was designed concurrently with a wide-body twinjet, the 767, and owing to shared features pilots can obtain a common type rating that allows them to operate both aircraft.

The 757 was produced in two fuselage lengths. The original 757-200 entered service in 1983; the 757-200PF, a package freighter (PF) variant, and the 757-200M, a passenger-freighter combi model, debuted in the late 1980s. The stretched 757-300, the longest narrow-body twinjet ever produced, began service in 1999. Passenger 757-200s have been modified to special freighter (SF) specification for cargo use, while military derivatives include the C-32 transport, VIP carriers, and other multi-purpose aircraft. Private and government operators have also customized the 757 for research and transport roles. All 757s are powered by Rolls-Royce RB211 or Pratt & Whitney PW2000 series turbofans.

Eastern Air Lines and British Airways placed the 757 in commercial service in 1983. The narrow-body twinjet succeeded earlier single-aisle airliners, and became commonly used for short and mid-range domestic routes, shuttle services, and transcontinental U.S. flights. After regulators granted approval for extended flights over water (ETOPS) in 1986, airlines also began using the aircraft for intercontinental routes. Major customers for the 757 included U.S. mainline carriers, European charter airlines, and cargo companies. The airliner has recorded eight hull-loss accidents, including seven fatal crashes, as of September 2015.

Production of the 757 ended in October 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 737 family. The last 757 was delivered to Shanghai Airlines in November 2005. In July 2015, 738 of the narrow-body twinjets were in airline service; Delta Air Lines is the largest operator with 138 aircraft.