Maryanne Amacher (born February 25, 1943) is an American composer of sound installations. Her pieces are almost exclusively site specific, the psychoacoustic illusions she creates being determined by the acoustics of the architecture. She has collaborated with David Behrman, Scott Fisher, Mark Trayle, and Alvin Curran.

Amacher released an album, Sound Characters (Making the Third Ear), on Tzadik, the title of which refers to the illusion created that the sounds are coming from within one's own head.

"When played at the right sound level, which is quite high and exciting, the tones in this music will cause your ears to act as neurophonic instruments that emit sounds that will seem to be issuing directly from your head ... (my audiences) discover they are producing a tonal dimension of the music which interacts melodically, rhythmically, and spatially with the tones in the room. Tones 'dance' in the immediate space of their body, around them like a sonic wrap, cascade inside ears, and out to space in front of their eyes ... Do not be alarmed! Your ears are not behaving strange or being damaged! ... these virtual tones are a natural and very real physical aspect of auditory perception, similar to the fusing of two images resulting in a third three dimensional image in binocular perception ... I want to release this music which is produced by the listener ..."
In 2005, she was awarded the Prix Ars Electronica in the "Digital Musics" category for her project "TEO! A sonic sculpture".