Duncan U. Fletcher High School, commonly referred to as Fletcher High, is a comprehensive public high school in Neptune Beach, Florida, United States. The school is one of 47 high schools in the Duval County School District. Like all Duval County schools, it is accredited through the Southern Association of Colleges and Schools.

Neptune Beach is a beachfront city east of Jacksonville in Duval County, Florida, United States. When the majority of Duval County communities consolidated with Jacksonville in 1968, Neptune Beach, along with Jacksonville Beach, Atlantic Beach and Baldwin remained quasi-independent. Like those other municipalities, it maintains its own municipal government but its residents vote in the Jacksonville mayoral election and are represented on the Jacksonville city council. As of the 2020 census, the population is 7,217. Neptune Beach is the smallest of the Jacksonville Beaches communities.