John Dewey High School is a public high school in Gravesend, Brooklyn, New York City. It was founded and based on the educational principles of John Dewey. The school, under the supervision of the New York City Department of Education, was named a New American High School in 2000.

The school opened on September 8, 1969, with 1,130 freshmen and sophomores. It grew in the next two academic years to include juniors and seniors. There currently are over 3,200 students. It counts among its alumni producer and director Larry Charles, filmmaker Spike Lee, Pulitzer Prize winner Donald Margulies, radio personality David Brody, photographer Gregory Crewdson, WWE wrestler Jayson Paul (aka JTG), scientist Robert Sapolsky, astrologer-journalist Eric Francis, news correspondent Ray Suarez, and film actress Michelle Ye.

John Dewey High School was also the first "educational-option" school in New York City, in which applicants are admitted through academic groups based on their citywide test scores: high, middle, and low-achieving. Dewey selects students from each of the three groups. Other schools in the city, such as Edward R. Murrow High School, Murry Bergtraum High School and Norman Thomas High School have since opened, following Dewey's "ed-op" system of admissions.