Pratt & Whitney's PW4000 is a family of high-bypass turbofan aircraft engines with certified thrust ranging from 52,000 to 99,040 pounds. It was built as the successor to the JT9D series engines and has found much wider application than its predecessor. It is divided into 3 distinct families based on fan diameter.

The first family is the 94-inch fan model with certified thrust ranging from 52,000 to 62,000 pounds. It powers the Airbus A310-300 and A300-600 aircraft and Boeing 747-400, 767-200/300 and MD-11 aircraft and is certified for 180-minute ETOPS if used in twinjets.

The second family is the 100-inch fan engine developed specifically for Airbus Industrie's A330 twinjet. It is certified from 64,500 to 68,600 pounds of thrust. It is the was the first engine to qualify for ETOPS (Extended-range Twin-engine Operations) prior to entering service in aviation history and is certified for 180-minute ETOPS.

The third family is the 112-inch fan engine developed specifically for Boeing's 777 where it was the launch engine.It is certified from 86,760 to 99,040 pounds of thrust.It entered service in June 1995 with United Airlines, already qualified for 180-minute ETOPS. It powers all the 777 versions except the -300ER.

The PW4000 features advanced technology materials and Full-Authority Digital Electronic Control (FADEC), for good fuel economy and reliability.