Marlboro High School (MHS) is the Marlboro Central School District's high school located in Marlboro, New York, United States.

Marlboro High School is a comprehensive, four-year institution for students in Grades 9-12. It is accredited by the Middle States Association of Schools. The curriculum consists of honor courses, college preparatory and occupationally related programs. The school also has a cooperative college bridge program with Ulster County Community College in the areas of English, history, government, economics, science, psychology, sociology, mathematics, and Spanish.

As of the 2022-23 school year, the school had an enrollment of 628 students and 52.91 classroom teachers (on an FTE basis), for a student–teacher ratio of 11.87:1. There were 194 students (30.9% of enrollment) eligible for free lunch and 37 (5.9% of students) eligible for reduced-cost lunch.

Marlboro offers a curriculum that includes Advanced Placement classes, college bridge courses, and other course offerings. College bridge courses are offered through Ulster County Community College. In addition, there are online courses offered.

Marlboro competes in Section 9 of the New York State Public High School Athletic Association (NYSPHAA).

• Rob Bell, former MLB pitcher
• Brian Benben, actor
• Dee Brown, former MLB player
• Scott Lobdell, comic book writer
• Margaret Russo (1931-2006), shortstop who played from 1950 through 1954 in the All-American Girls Professional Baseball League
• Snooki, MTV television personality
• Brianna Titone, Colorado state representative

• School website
• Marlboro grad DeMartine named to softball Hall