The Roslyn Union Free School District (also known as Union Free School District No. 3) is an American public school district located in Nassau County, on Long Island in New York, United States. The district serves the entirety of the villages of Roslyn and Roslyn Estates, in addition to parts of the villages of East Hills, Flower Hill, North Hills, and Roslyn Harbor, and parts of the hamlets of Greenvale and Roslyn Heights.