The Pratt & Whitney J57 is an axial-flow turbojet engine developed by Pratt & Whitney in the early 1950s. The J57 was the first 10,000 lbf (45 kN) thrust class engine in the United States. It was also the first two-spool turbojet to run, a few months before the similar Bristol Olympus in the UK.

Pratt & Whitney is an American aerospace manufacturer with global service operations. It is a subsidiary of RTX Corporation. Pratt & Whitney's aircraft engines are widely used in both civil aviation and military aviation. Its headquarters are in East Hartford, Connecticut. The company is the world's second largest commercial aircraft engine manufacturer, with a 35% market share as of 2020. In addition to aircraft engines, Pratt & Whitney manufactures gas turbine engines for industrial use, marine propulsion, and power generation. In 2017, the company reported that it supported more than 11,000 customers in 180 countries around the world.