Theatre of Voices is a vocal ensemble founded by baritone Paul Hillier in 1990; it focuses on early music and new music.

The ensemble was formed by Paul Hillier while he was teaching at the University of California, Davis, as an avenue to performing more contemporary music while his other group, the Hilliard Ensemble, focused primarily on early music. Originally based in the United States, members of the group originated from both the United States and England. After Hillier's move to Copenhagen in 2003, membership in the group became more international, with members drawn from Denmark, Poland, England, and the United States.