Centre professionel et technique Minto

There are numerous secondary schools in Ontario. Secondary education policy in the Canadian province of Ontario is governed by the Ministry of Education. 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. 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.

Public secular secondary schools may operate under a number of designations, including collegiate institute, école secondaire, high school, and secondary school. Public separate secondary schools are typically named academy, Catholic high school, Catholic secondary school, college school or école secondaire catholique.