Holy Heart of Mary High School is a public high school located in St. John's, Newfoundland and Labrador, Canada. Built in the 1950s by the Presentation sisters, it was originally an all-girls school called "Holy Heart of Mary Regional High School for Girls". The first classes were held on November 17, 1958. Historically the student population has often exceeded 1000 students, making it one of the largest in the province.