Summer school enrolment rates are up in southern Quebec, and many are blaming the province's high school exams.

The Lester B. Pearson School Board says it has 30 per cent more students are heading to summer school this year, compared to 2011.

That increase coincides with higher failure rates for science, history, and math exams in Gr. 10 and 11.

Parents and students say they were caught off guard.

The school board has to bring in more teachers and open more summer school centres to handle larger numbers.

WATCH: Sabrina Marandola reports on summer school enrolment