The Butler High School Bulldogs participate in the North Jersey Interscholastic Conference, which is comprised of small-enrollment schools in Bergen, Hudson, Morris and Passaic counties, and was created following a reorganization of sports leagues in Northern New Jersey by the New Jersey State Interscholastic Athletic Association (NJSIAA). Until the 2018–19 school year, the school had been part of the Northwest Jersey Athletic Conference, but shifted to the NJIC to compete against other smaller schools. Before the NJSIAA's 2010 realignment, the school had competed in the Northern Hills Conference an athletic conference that included public and private high schools in Essex, Morris and Passaic counties. With 374 students in grades 10–12, the school was classified by the NJSIAA for the 2019–20 school year as Group I for most athletic competition purposes, which included schools with an enrollment of 75 to 476 students in that grade range. The school was classified by the NJSIAA as Group I North for football for 2018–2020.