West Windsor-Plainsboro High School South, commonly referred to locally as “South”, is a four-year comprehensive public high school located in Princeton Junction in Mercer County, New Jersey, United States, serving students in ninth through twelfth grades. The school is part of the West Windsor-Plainsboro Regional School District, a regional school district serving students from West Windsor (in Mercer County) and Plainsboro Township (in Middlesex County). It is one of two high schools in the district, the other being West Windsor-Plainsboro High School North.