St. John's-Kilmarnock School (SJK) is an elite, private school in Waterloo Region, Ontario, operating under the International Baccalaureate program. The school is widely described as one of the country's most prestigious preparatory schools, and has graduated many notable alumni. SJK has 425 students and is a highly selective school, accepting approximately 20% of applicants in 2021. The school attracts a significant minority of international boarding students and has a generous financial aid program, with more than $500,000 being awarded annually to Canadian citizens.