The purpose of this paper is to describe the research program in aircraft acoustics being conducted by the NASA–Langley Research Center. The program includes research to understand, predict, and reduce the sources of aircraft noise; to quantify the transmission of noise through the atmosphere and/or aircraft structures; and to define the effects of noise on people and structures. The research is focused on a broad range of aircraft with emphasis on advanced subsonic transports including conventional and tiltrotor rotorcraft, supersonic transports, high-performance military vehicles and hypersonic configurations. Specialty areas of research include computational aeroacoustics, jet noise, rotating blade acoustics, and structural and subjective acoustics. The resulting technology is used to design and operate aircraft to reduce community noise impact and/or to minimize the effects of noise on structural integrity and interior noise.