Unionville High School is a public high school of the York Region District School Board in Ontario, Canada. It is located west of the community of Unionville in the city of Markham. The school is located next to the Markham Civic Centre and the Markham Theatre.

Unionville High School is most well known for its enriched arts program, Arts Unionville (formerly known as Arts York). The school was purpose-built to house this regional arts program, therefore it has enhanced arts facilities. Arts Unionville is divided into 4 categories: visual arts, music, dance, and drama. To determine if they will be a good fit for the program, grade eight to nine students are required to audition and participate in a wide-ranging conversation to determine. It is possible to enter the program in the upper grades, as well, if there is room.