The Parsippany High School Red Hawks participate in the Northwest Jersey Athletic Conference, which is comprised of public and private high schools covering Morris, Sussex and Warren counties, and was established by the New Jersey State Interscholastic Athletic Association (NJSIAA) following a reorganization of sports leagues in Northern New Jersey. Prior to the NJSIAA's 2010 realignment, the school had competed as part of the Iron Hills Conference, which included public and private high schools in Essex, Morris and Union counties. With 672 students in grades 10-12, the school was classified by the NJSIAA for the 2019–20 school year as Group II for most athletic competition purposes, which included schools with an enrollment of 486 to 758 students in that grade range. The football team competes in the American Blue division of the North Jersey Super Football Conference, which includes 112 schools competing in 20 divisions, making it the nation's biggest football-only high school sports league. The school was classified by the NJSIAA as Group II North for football for 2018–2020.