Brentwood High School is a public high school located in Brentwood, Pennsylvania, outside of Pittsburgh, that serves students in grades 9 through 12.

The high school first started in 1925 in the basement of the existing Elroy Elementary School and only taught the ninth grade. In 1932, a new high school was built alongside the current Brentwood Park. However, this was only one building. The building received its first addition in 1939 to accommodate the rapid increase in population. Another addition was completed in 1959, which offered more rooms and the school's first gymnasium. A new four-story building was constructed in 1971 that included a swimming pool and more classrooms.

The building had its latest renovation in 1999 in which a new academic wing was constructed. While the new wing was being built, the classrooms in the 1971 building were demolished and replaced with the second gymnasium, alongside more extracurricular rooms. This is now where grades 9-12 are taught, with grades 6-8 being taught in the 1932-59 buildings.