Montclair High School is a comprehensive four-year public high school located in Montclair, in Essex County, in the U.S. state of New Jersey, serving students in ninth through twelfth grades as the lone secondary school of the Montclair Public School District. The school has been accredited by the Middle States Association of Colleges and Schools Commission on Elementary and Secondary Schools since 1928.

As of the 2024–25 school year, the school had an enrollment of 1,925 students and 149.6 classroom teachers (on an FTE basis), for a student–teacher ratio of 12.9:1. There were 275 students (14.3% of enrollment) eligible for free lunch and 69 (3.6% of students) eligible for reduced-cost lunch.