Sir John A. Macdonald Secondary was a secondary school in Hamilton, Ontario, before it closed in 2019. At the time of closing, it was the largest high school in the Hamilton-Wentworth District School Board (HWDSB). The school opened in 1970 and had an enrollment of 1250 students in 2009. At its peak, the student body represented over 80 countries of origin and the students had over 50 different native languages. The building has an auditorium that seats 750 people. The building is located at 130 York Boulevard, Hamilton, Ontario, close to the city Public Library and across the street from the Copps Coliseum and Lloyd D. Jackson Square Mall.