Mandaluyong High School is a high school located in Mandaluyong, Metro Manila, Republic of the Philippines. Founded in 1977 through the initiative of the late Mayor Renato I. Lopez, Mandaluyong High School is the oldest public secondary school of Mandaluyong. Due to its scarcity of classrooms during its pioneering years, some classes had to be held in three different elementary schools. Evolving into a comprehensive four-year public high school with the construction of additional buildings and various facilities, the school now educates around 3,800 students in six buildings. With 55 classrooms, it has the largest building of all the city's schools.