The Holmdel High School Hornets compete in Division A Central of the
Shore Conference, an athletic conference comprised of public and private high schools in Monmouth and
Ocean counties along the
Jersey Shore. The league operates under the jurisdiction of the
New Jersey State Interscholastic Athletic Association (NJSIAA). With 712 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 school was classified by the NJSIAA as Group III South for football for 2024–2026, which included schools with 695 to 882 students. The school participates in a joint ice hockey team with
Marlboro High School as the host school / lead agency. The co-op program operates under agreements scheduled to expire at the end of the 2023–24 school year. The girls' tennis team has won the Group I title in 1978 (defeating
Chatham Township High School in the finals), Group II in 1999 (vs.
Chatham High School), 2014 (vs.
Summit High School), 2015 (vs.
Ramapo High School), 2016 (vs.
Haddonfield Memorial High School), 2017 (vs. Haddonfield) and 2018 (vs.
Northern Valley Regional High School at Demarest) and won in Group III in 2005 (vs.
Wall High School); the program's seven state titles are tied for tenth-most in the state. Holmdel won the
Tournament of Champions in 2005 against runner-up
Westfield High School. The 1978 team won the Group I state title in the tournament final at
Princeton University with a 4-1 win against a Chatham Township team that beat Holmdel 4-1 the previous year. The 1999 team won against
Pascack Hills High School 4-1 in the semis and defeated Chatham 3-2 in the tournament finals at
Mercer County Park. The team won the program's fifth consecutive Group II title with a 3-2 win in 2018 against Northern Valley at Demarest. The girls cross country team won the Group II state championship from 1982 to 1984 and 2019. The boys' tennis team won the Group II state championship in 1983 (against runner-up
Tenafly High School), 1984 (vs.
Moorestown High School), 2002 (vs. Moorestown), 2012 (vs.
Haddonfield Memorial High School), 2013 (vs.
Bernards High School), 2015 (vs.
Summit High School), 2016 (vs.
West Essex High School), 2017 (vs.
Northern Valley Regional High School at Demarest) and 2018 (vs.
Haddonfield Memorial High School). The program's nine state titles are tied for tenth-most in the state. The team won the 2002
Tournament of Champions with a 3-2 win against
Dwight-Englewood School. A 5-0 win against Northern Valley Demarest in 2017 earned the team their third straight Group II title. The 2018 team won the program's fourth consecutive Group II title with a 4-1 win against Haddonfield in the finals at
Mercer County Park. The boys cross country team won the Group II state championship in 1994, 1995, 2001, 2011 and 2012. In 1998 and 1999, the boys' basketball team won back-to-back Group II state championships by defeating
West Morris Mendham High School both seasons. The 1998 team won the program's first state title with a 67-52 against West Morris Mendham in the Group II championship game. The team won its second consecutive Group II title in 1999 with a 55-51 win against West Morris Mendham in the tournament final at the
Atlantic City Convention Hall. The 1999 team went on to defeat
Parsippany High School in the quarterfinals of the
Tournament of Champions by a score of 77-55 before falling to eventual ToC champion
Seton Hall Preparatory School by a score of 63–42 in the semifinals. In 2001, the baseball team won the NJSIAA Central Jersey Group II state sectional championship, beating
Spotswood High School by a score of 7–1. The field hockey team won the Central Jersey Group II state sectional title in 2007 and the North II Group III title in 2008. In 2007, the field hockey team won the Central Jersey Group II sectional championship with a 2–1 win over
Allentown High School in the tournament final. The boys' soccer team won the Group III state championship in 2010 (defeating
Chatham High School in the tournament final), and won the Group II title in 2017 (vs.
Dover High School) and 2018 (vs.
Glen Rock High School). In 2006, the boys' soccer team won the North II Group III state sectional championship, beating
Voorhees High School 4–2, before losing in the Group III state championship game by a score of 3–0 to
Ramapo High School. In 2010, the team finished the season with a 22-1 record, having won the Group III title, the program's first, with a 2–1 win over Chatham in the championship game. The victory was the first and only Group III championship won by Holmdel in any sport. The 2017 team finished the season with a 21-1-1 record after winning the program's first championship in the Shore Conference Tournament title with a 7-1 win against
Ocean Township High School in the finals and taking the Group II title with a 4-1 win against Dover in the championship game played at
Kean University. The 2018 team won the program's third state title and second in two years after a 3-1 win against Glen Rock in the Group II finals, to finish the season 22-0-1. Holmdel girls' soccer varsity won the NJSIAA Group II state championship in 2014, the program's first, with a 1–0 victory in the tournament final against
Ramapo High School. ==Controversy==