Diamanda Galás (born August 29, 1955) is an American-born avant-garde performance artist of Greek origin, vocalist, keyboardist and composer.
Known for her expert piano as well as her distinctive, operatic voice, which has a three and a half octave range, Galás has been described as "capable of the most unnerving vocal terror" . Galás often shrieks, howls, and seems to imitate glossolalia in her performances. Her works largely concentrate on the topics of suffering, despair, condemnation, injustice and loss of dignity. Critic Robert Conroy has said that she is 'unquestionably one of the greatest singers America has ever produced', and comparisons are frequently made between her and another soprano of Greek origin, Maria Callas.
She has worked with many avant-garde composers including, Iannis Xenakis and Vinko Globokar. She made her performance debut at the Festival d'Avignon in France as the lead in Globokar's opera, Un Jour Comme Un Autre. The work was sponsored by Amnesty International. She also contributed her voice to Francis Ford Coppola's film Dracula (1992) and appeared on the film's soundtrack.