Greenwich High School is a four-year public high school in Greenwich, Connecticut, United States. The school is part of the Greenwich Public Schools system and serves roughly 2,700 students.

Greenwich is a town in southwestern Fairfield County, Connecticut, United States. At the 2020 census, it had a population of 63,518. Greenwich is a principal community of the Bridgeport–Stamford–Norwalk–Danbury metropolitan statistical area, which comprises all of Fairfield County, and is part of the Western Connecticut Planning Region. The town is the southwesternmost municipality in both the State of Connecticut and the six-state region of New England. The town is named after Greenwich, a royal borough of London in the United Kingdom.