Middlesex High School (MHS) is a four-year comprehensive public high school located in the center of Middlesex, Middlesex County, in the U.S. state of New Jersey, serving students in ninth through twelfth grades as the lone secondary school of the Middlesex Board of Education. The school is surrounded by Mountain View Park and all of its athletic complexes, including Memorial Field.

As of the 2024–25 school year, the school had an enrollment of 597 students and 55.0 classroom teachers (on an FTE basis), for a student–teacher ratio of 10.9:1. There were 211 students (35.3% of enrollment) eligible for free lunch and 62 (10.4% of students) eligible for reduced-cost lunch.School data for Middlesex High School, National Center for Education Statistics. Accessed January 15, 2026.

History The new high school opened in September 1959 with students in ninth and tenth grades. Prior to that time, students from Middlesex had attended Bound Brook High School. Middlesex students entering eleventh and twelfth grades continued their education at the Bound Brook school through graduation.Geraghty, Gloria. "Record 30,000 Ready for School Bells", The Daily Home News, September 5, 1959. Accessed February 16, 2022, via Newspapers.com. "Bound Brook will lose 9th and 10th graders from Middlesex to the new Middlesex High School. Eleventh and 12th graders from Middlesex will continue in Bound Brook High School until they complete their secondary school education."

Awards, recognition and rankings The school was the 177th-ranked public high school in New Jersey out of 339 schools statewide in New Jersey Monthly magazine's September 2014 cover story on the state's "Top Public High Schools", using a new ranking methodology.Staff. "Top Schools Alphabetical List 2014", New Jersey Monthly, September 2, 2014. Accessed September 5, 2014. The school had been ranked 155th in the state of 328 schools in 2012, after being ranked 183rd in 2010 out of 322 schools listed.Staff. "The Top New Jersey High Schools: Alphabetical", New Jersey Monthly, August 16, 2012. Accessed August 28, 2012. The magazine ranked the school 169th in 2008 out of 316 schools.Staff. "2010 Top High Schools", New Jersey Monthly, August 16, 2010. Accessed March 18, 2011. The school was ranked 148th in the magazine's September 2006 issue, which surveyed 316 schools across the state."Top New Jersey High Schools 2008: By Rank", New Jersey Monthly, September 2008, posted August 7, 2008. Accessed August 19, 2008. Schooldigger.com ranked the school 158th out of 381 public high schools statewide in its 2011 rankings (an increase of 3 positions from the 2010 ranking) which were based on the combined percentage of students classified as proficient or above proficient on the mathematics (83.6%) and language arts literacy (92.4%) components of the High School Proficiency Assessment (HSPA).New Jersey High School Rankings: 11th Grade HSPA Language Arts Literacy & HSPA Math 2010-2011, Schooldigger.com. Accessed March 6, 2012.

Athletics The Middlesex High School Blue JaysMiddlesex High School, New Jersey State Interscholastic Athletic Association. Accessed October 20, 2020. compete in the Greater Middlesex Conference, which includes public and private high schools located in the greater Middlesex County area and operates under the supervision of the New Jersey State Interscholastic Athletic Association (NJSIAA).League & Conference Officers/Affiliated Schools 2020-2021, New Jersey State Interscholastic Athletic Association. Accessed October 20, 2020. With 462 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.NJSIAA General Public School Classifications 2019–2020, New Jersey State Interscholastic Athletic Association. Accessed November 20, 2020. The football team competes in Division 1A of the Big Central Football Conference, which includes 60 public and private high schools in Hunterdon, Middlesex, Somerset, Union and Warren counties, which are broken down into 10 divisions by size and location.Kinney, Mike. "Big Central revises 2020 football schedule for its shortened inaugural season", NJ Advance Media for NJ.com, August 12, 2020. Accessed April 18, 2021. "The newly formed Big Central Football Conference has released a revised 2020 schedule for its inaugural season.... the BCFC is comprised of schools from Middlesex, Union, Somerset, Hunterdon and Warren counties." The school was classified by the NJSIAA as Group I South for football for 2024–2026, which included schools with 185 to 482 students.NJSIAA Football Public School Classifications 2024–2026, New Jersey State Interscholastic Athletic Association, updated September 2024. Accessed September 1, 2024.

The school participates as the host school / lead agency for a joint wrestling team with Dunellen High School. Middlesex and Somerville High School are partners in a co-op ice hockey program with Bernards High School. These co-op program operate under agreements scheduled to expire at the end of the 2023–24 school year.NJSIAA Winter Cooperative Sports Programs, New Jersey State Interscholastic Athletic Association. Accessed December 1, 2020.

The football team won the NJSIAA Central Jersey Group II state sectional championship in 1974, then in Central Jersey Group I in 1981, 1982, 1984 and 2017.NJSIAA Football History, New Jersey State Interscholastic Athletic Association. Accessed May 1, 2023. The 1974 team finished the season with a 9-0-1 record after winning the first Central Jersey Group II sectional title of the playoff era with a 24–6 victory against Hillsborough High School indoors at the Atlantic City Convention Hall."Middlesex, Ramapo Capture Jersey Football Titles", The New York Times, December 9, 1974. Accessed December 28, 2020. "Middlesex defeated Hillsborough, 24-6, for the Central Jersey, Group 2 title, and Ramapo routed Dumont, 46-14, for the North Jersey, Section 1, Group 3 crown today in Convention Hall. This was the final day of the state's first high school football playoffs. Bob Parlo, the Middlesex quarterback, scored one touchdown on a plunge, threw his 14th scoring pass of the season—to Carl Mayer—intercepted two passes and averaged 40 yards a punt to spark his team, which finished with a 9-0-1 won-lost-tied mark." The 1994 team defeated four-time defending champion South River High School by a score of 14–7 to win the Central Jersey Group I title and finish the season 10–1.Merrill, Everett. "Middlesex silences South River", Courier News, December 7, 1981. Accessed January 20, 2021, via Newspapers.com. "Not only was the South River High mascot resting, but just a short 30 yards up the bench the entire football team was quiet. A dynasty had just been silenced. Middlesex High School had just ended South River's four-year domination of Central Jersey Group 1 football by stopping the Rams 14-7. The victory gave Middlesex its first state championship since 1974, when the Blue Jays bumped off Hillsborough.... Middlesex ended its season at 10-1, the best fall it has since '74." In a turnaround from winning only one game in 2016, the football team won the 2017 Central Jersey Group I state sectional tournament with a 33–21 win at Alumni Stadium at Kean University against seventh-seeded Point Pleasant Beach High School in the tournament final.Lanni, Patrick. "Middlesex fights off Point Pleasant Beach to win CJ1 title, caps turnaround season", NJ Advance Media for NJ.com, December 2, 2017. Accessed December 5, 2017. "Middlesex won one game in 2016.... Middlesex never trailed Saturday as it had an answer every time Point Pleasant Beach threatened and held on for a 33-21 victory Saturday in the Central Jersey, Group 1 final at Kean University's Alumni Stadium in Union.... That challenge ultimately secured Middlesex's first sectional title since 1984.""Football - 2017 NJSIAA Central, Group 1 Playoffs", NJ.com. Accessed December 5, 2017. Middlesex ended its Thanksgiving Day rivalry with Dunellen High School in 2019, after 21 games in the annual series.Tufaro, Greg. "NJ football: Middlesex-Dunellen Thanksgiving rivalry comes to an end", Courier News, October 25, 2018. Accessed November 18, 2020. "Next month’s 21st annual meeting between the Middlesex and Dunellen high school football programs will mark the last Thanksgiving Day game for the border rivals. Middlesex athletics director Mike O’Donnell said the NJSIAA’s revamped postseason format, which creates a three-week layoff to Thanksgiving Day for nonplayoff qualifiers who don’t play two regional crossover games, led to the end of his school’s holiday meeting with Dunellen."

The boys' wrestling team won the Central Jersey Group I state sectional title in 1985 and 1986.Boys Wrestling Championship History: 1934–2025, New Jersey State Interscholastic Athletic Association, updated February 2026. Accessed March 1, 2026.