Secondary education in Ontario includes Grades 9 to 12.
The following list includes public secular institutions, public separate schools, and privately managed independent schools in Ontario.
[1] All public schools in Ontario (secular and separate) operate as a part of either an English first language school board or a French first language school board.
Although Ontario's secular and separate school systems are both considered public, colloquially the term public school typically distinguishes a secular institution from its separate counterparts: institutions operated by a public secular school board are typically referred to as public schools, whereas institutions operated by a public separate school board are typically referred to as Catholic schools.
[note 1] Public secular secondary schools may operate under a number of designations, including collegiate institute, école secondaire, high school, and secondary school.