The Somerville High School Pioneers have historically competed in the Skyland Conference, consisting of public and non-public high schools located in west Central Jersey. With 881 students in grades 10–12, the school was classified by the NJSIAA for the 2019–20 school year as Group III for most athletic competition purposes, which included schools with an enrollment of 761 to 1,058 students in that grade range. The Skyland Conference football programs have re-organized into the Mid-State 38, adding Union County schools to the existing mix of Somerset, Hunterdon and Warren County programs. The school was classified by the NJSIAA as Group III South for football for 2018–2020.