In some countries thirteenth grade or grade thirteen is or was the final year of secondary school.
The Ontario Academic Credit (OAC) (French: Cours préuniversitaire de l'Ontario or CPO) was a fifth year of secondary school education designed for students preparing for post-secondary education that previously existed in the province of Ontario, Canada. The OAC curriculum was codified by the Ontario Ministry of Education in Ontario Schools: Intermediate and Senior (OS:IS) and its revisions. The Ontario education system had five years of secondary education, the fifth year known as "grade 13" from 1921 to 1988. Then grade 13 was replaced in 1984 by the OAC for students starting high school (grade 9). The OAC continued to act as a fifth year of secondary education until it was phased out in 2003.
In Germany, students wishing to take the Abitur usually had to attend a thirteenth grade, but most states are shortening the Gymnasium (the university-bound secondary school system in Germany) from nine to eight years.
- Brady, Patrick; Allingham, Philip (18 November 2010). "Pathways to university: The "Victory Lap" Phenomenon in Ontario" (PDF). Canadian Journal of Educational Administration and Policy (113).