The Mount St. Dominic Academy Lady Lions compete in the Super Essex Conference which is comprised of public and private high schools in Essex County and was established following a reorganization of sports leagues in Northern New Jersey by the New Jersey State Interscholastic Athletic Association (NJSIAA). Before the NJSIAA's 2010 realignment, the school had competed in the Northern Hills Conference an athletic conference which included schools located in Essex, Morris and Passaic counties. With 396 students in grades 10-12, the school was classified by the NJSIAA for the 2019–20 school year as Non-Public A for most athletic competition purposes, which included schools with an enrollment of 381-1,454 students in that grade range (equivalent to Group I for public schools). The Mount offers a variety of both Varsity and JV teams, including sports such as basketball, bowling, cross country, field hockey, golf, lacrosse, soccer, softball, swimming, tennis, track, and volleyball. Approximately one half of the students participate in athletics.