Centereach High School is a public high school in the Middle Country Central School District located in Centereach, Suffolk County, Long Island, New York. It teaches a college preparatory curriculum for grades nine through twelve. The total minority enrollment is 26%, and 33% of students are economically disadvantaged. Centereach High School is 1 of 2 high schools in the Middle Country Central School District.

As of the 2014–15 school year, the school had an enrollment of 1,552 students and 106.5 classroom teachers (on an FTE basis), for a student–teacher ratio of 14.6:1. There were 308 students (19.8% of enrollment) eligible for free lunch and 115 (7.4% of students) eligible for reduced-cost lunch.