Thornhill Secondary School (TSS) is a secondary school in Thornhill, Ontario, Canada. Founded in 1955, the school is administered by the York Region District School Board system.

History

Originally it served as an elementary school, but in 1956 it opened as a full-time high school with 600 students. The TSS library was established in 1960 and renovated in 2007. In 1962, the school increased its classrooms from 30 to 47 and added 32 members to its original faculty of 29. By 1962, 1090 students were enrolled. A technical and commercial wing was built in 1961. In 1976, the school undertook a major renovation. That same year, the drama program started and the music program expanded. In 1999, an expanded science wing was constructed to accommodate an overflow of students. A new library and school hallway connecting science to the technologies and music was completed in June 2007.

Notable alumni