Roslyn Harbor is a village in Nassau County, on the North Shore of Long Island, in New York, United States. It is considered part of the Greater Roslyn area, which is anchored by the Incorporated Village of Roslyn. The population was 1,067 at the time of the 2020 census. The Incorporated Village of Roslyn Harbor is located mostly in the Town of North Hempstead with small sections in the Town of Oyster Bay.