Diamanda Galás (born August 29, 1955) is an American avant-garde composer, vocalist, pianist, organist, performance artist, and painter.

Galás has been described as “capable of the most unnerving vocal terror.” Her works largely concentrate on the topics of AIDS, mental illness, despair, injustice, condemnation, and loss of dignity. She has worked with many avant-garde composers, including Iannis Xenakis, Vinko Globokar and John Zorn, and also collaborated with jazz musician Bobby Bradford, and John Paul Jones, former bassist of Led Zeppelin.