Theatre of Voices is one of the most admired and versatile vocal ensembles from the late 20th century. Led by founder and artistic director Paul Hillier, the group has performed a variety of works, including Medieval chant, Renaissance works by Lassus and Tallis, popular Christmas carols, and 20th century works by composers like Pärt and Cage. The ensemble has made numerous recordings, most often for the Harmonia Mundi and Dacapo labels. Its size has ranged from one to nearly two dozen singers over its history.

Theatre of Voices gave its first official concert in June 1992 at the Berkeley Early Music Festival. Hillier had actually presented concerts of modern music in 1989 in which his early music vocal group, the Hilliard Ensemble, used the name Theatre of Voices. The development of the group that would become Theatre of Voices began in 1990 when Hillier took a teaching position at the University of California. The formation was not finalized until that 1992 debut concert. The group later moved its base of operations to Bloomington, Indiana, where Hillier relocated to serve on the faculty of Indiana University School of Music (Early Music Institute). When Hillier moved to Copenhagen in 2003, the ensemble also expanded its geographical horizons.

Theatre of Voices' first recording, William Byrd: Motets Mass for Four Voices, was issued in 1994 on the Harmonia Mundi label. By then, the group was carrying a busy schedule and, over the next decade, would appear at major concert venues throughout the Americas and Europe, including New York, Paris, and Berlin. It appeared on a six-part nationwide syndicated radio broadcast for the series Millennium of Music and also on the radio program St. Paul Sunday Morning. In 1997, Oxford University Press published Hillier's book Arvo Pärt. That same year, Hillier led Theatre of Voices in a recording of Pärt's sacred works on Harmonia Mundi, entitled De Profundis, which made Billboard's Top Ten. A second popular recording of the composer's works by Theatre of Voices, I Am the True Vine, was issued on the same label in 2000.

The ensemble has remained active both in the concert hall and on recordings in the new century. The 2006 schedule included a tour of the U.K. and an appearance at the ILIOS Festival in Norway with the ensemble presenting Stockhausen's Stimmung, among other works. That year, the group released Cantigas on Harmonia Mundi. The group's world premiere recording of David Lang's Pulitzer Prize-winning Little Match Girl Passion won a Grammy Award in 2010 for Best Small Ensemble Performance. The group has continued to collaborate with composers, including Kaija Saariaho, John Luther Adams, and Michael Gordon, among many others. In 2019, Theatre of Voices premiered Gordon's choral work A Western. The group was heard in 2022 on the Deutsche Grammophon album Jóhann Jóhannsson: Drone Mass with the American Contemporary Music Ensemble (ACME). ~ Robert Cummings, Rovi