The Lockheed/Boeing/General Dynamics YF-22 is an American single-seat, twin-engine fighter aircraft technology demonstrator designed for the United States Air Force (USAF). The design was a finalist in the USAF's Advanced Tactical Fighter (ATF) competition, and two prototypes were built for the demonstration/validation phase of the competition. The YF-22 won the contest against the Northrop YF-23 for full-scale development, and the design was developed into the Lockheed Martin F-22 Raptor. The YF-22 has a similar aerodynamic layout and configuration as the F-22, but with notable differences in the overall shaping such as the position and design of the cockpit, tail fins and wings, and in internal structural layout.

The Advanced Tactical Fighter (ATF) was a program undertaken by the United States Air Force to develop a next-generation air superiority fighter to counter emerging worldwide threats, including Soviet Sukhoi Su-27 and Mikoyan MiG-29 fighters under development in the 1980s, Beriev A-50 airborne warning and control system (AWACS), and increasingly sophisticated surface-to-air missile systems. Lockheed and Northrop were selected in 1986 to respectively develop the YF-22 and the YF-23 technology demonstrator aircraft for the program's demonstration and validation (Dem/Val) phase. These aircraft were evaluated in 1991 and the Lockheed design was selected for full-scale development, or engineering and manufacturing development (EMD), and later developed into the F-22 Raptor for production and operational service.