Founded in 1968 by Ruby Mercer and Lloyd Bradshaw, the Canadian Children's Opera Chorus (CCOC) is unique in Canada as the only permanent children's opera chorus which develops and produces new operas for children. The impressive repertoire of operas commissioned by the CCOC includes The Hobbit (Dean Burry), The Star Child (John Greer/Ned Dickens), The Snow Queen (John Greer/Jeremy James Taylor), A Midwinter Night's Dream (Harry Somers/Tim Wynne-Jones), Dr. Canon's Cure (Derek Holman/Robertson Davies), and Chip and His Dog (Gian Carlo Menotti).

Today, the CCOC Principal Chorus consists of 80 girls and boys who perform operatic and choral repertoire under Artistic Director Ann Cooper Gay and participate as the children's chorus in all Canadian Opera Company productions requiring children's voices. The Principal Chorus also enjoys working with other arts organizations, including the Toronto Symphony Orchestra, the University of Toronto Faculty of Music, and the National Ballet of Canada. Since its inception in 1968, the CCOC's performances have grown from fourteen to over fifty per season.

To accommodate the growing interest of younger musicians aged 7 to 11, two Apprentice Choruses were established in 1988. Under the direction of Ann Cooper Gay, Teodora Georgieva and Bronwen Low along with Drama Coach Joanne Mitchell, the Apprentice Chorus programme provides instruction in vocal technique, acting, theory and solfege.

In 1999 the Ruby Chorus, named in honour of the CCOC's founder Ruby Mercer, was created to introduce 5 and 6 year olds to the world of music and drama through singing games and regular eurhythmic training.

The Canadian Youth Opera Chorus (CYOC) was formed in 2002 to provide further choral and operatic training for girls (16 to 19) and boys (14 to 19), under the direction of Ann Cooper Gay. The repertoire is drawn from opera, oratorio, choral masterpieces and musical theatre, as well as solo/ensemble selections from opera and musical theatre.

The CCOC is committed to fostering a lifelong enjoyment of the arts in children by introducing them to the magic of live opera, both as performers and as members of its audiences.