The St. Mary School Children's Theatre is organized and directed by St. Mary School staff members and volunteers. Auditions for the SMS Children's Theatre are typically held in January and are open to all students. Rehearsals are held after school from January until May, when the play/musical goes live. Past performances include The Little Mermaid, the Wizard of Oz and the Jungle Book. The performance is always held in the McGivney Building behind the Basilica of the Immaculate Conception Church.