The Mount Olive High School Marauders compete in the
Northwest Jersey Athletic Conference, which is comprised of public and private high schools located in Morris,
Sussex and
Warren counties, operating under the supervision of the
New Jersey State Interscholastic Athletic Association (NJSIAA). Prior to the NJSIAA's 2010 realignment, the school had competed as part of the
Iron Hills Conference, which included high schools in
Essex, Morris and
Union counties. With 1,158 students in grades 10-12, the school was classified by the NJSIAA for the 2019–20 school year as Group IV for most athletic competition purposes, which included schools with an enrollment of 1,060 to 5,049 students in that grade range. The football team competes in the Freedom 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 IV North for football for 2024–2026, which included schools with 893 to 1,315 students. Students are eligible to participate in interscholastic sports offered in the fall, winter, and spring seasons. Fall sports include boys/girls soccer, girls tennis, boys/girls cross country, boys football, girls cheerleading, girls volleyball, and girls field hockey. Winter sports include boys/girls basketball, boys/girls indoor track, boys wrestling, and boys/girls swimming. Spring sports include boys/girls track, boys/girls lacrosse, boys baseball, girls softball, boys/girls golf, girls flag football, and boys tennis. The ice hockey partnership with Mount Olive started in the 2014-15 school year and plays under the Mount Olive name. Mount Olive High School added new athletic facilities constructed during the 2005-2007 school years. New facilities include a turf field, auxiliary gym, weight room, dance room, training room, and new offices for coaches. In 2017–18, additional facilities were added, including new stadium seating for the turf football field and a dome to be used over the soccer field in the winter. The field hockey team won the North II Group II state sectional championship in 1981, won the North II Group III title in 1988, 1995 and 1998, and won the North I Group III title in 1999, 2001, 2003 and 2004. The 2003 field hockey team won the North I, Group III sectional title with a 1–0 win against
High Point Regional High School. The 2004 team repeated the title with a 3–0 win over
Wayne Hills High School. The girls' cross country team won the Group III state championship in 1989 and 2013. The team has won the North Jersey sectional title 11 times in their history starting with five in a row from 1977–1981. The boys' soccer team won the North I, Group III state sectional championship in 1999 with a 2–1 win against
Northern Highlands Regional High School in the tournament final. In 2002, the football team finished the season with an 11-1 record after winning the North II, Group III sectional championship with a 14–13 victory against
Jefferson Township High School in the championship game, after holding off a late rally by Jefferson. The boys' wrestling team won the North II Group III state sectional title in 2002 and the North I Group IV title in 2020 and 2022–2024; the team won the Group IV state championship in 2022. In 2008, the softball team won the NJSIAA/Blue Ribbon Awards North I, Group III sectional tournament with a 1–0 shutout of
Montville Township High School. In 2011, the basketball team won their first conference championship in school history. In 2012, the Marauders won their second straight conference title, sharing it with
Sparta High School and
Pope John XXIII Regional High School. They also made it to the finals for their County Tournament for just the second time in school history. However, after tying the game up with 11 seconds to play, they lost by 2 points when Chatham scored a layup with 5 seconds left. The following season, in 2013, the Marauders made it to the Morris County Championship once again, this time defeating
Chatham High School. The 2014 team went on to another MCT Championship with a victory over Morristown, being told as the greatest basketball game ever in Morris County history. The ice hockey team won the Haas Cup in 2014 with a 3-2 overtime win against
Madison High School in the championship game. ==Fine and performing arts==