Jupiter Island is a town located on the barrier island also called Jupiter Island, in Martin County, Florida, United States; the town is part of Florida's Treasure Coast. It is part of the Port St. Lucie metropolitan area. The Town of Jupiter Island is located next to the unincorporated community of Hobe Sound. The population of Jupiter Island was 804 at the 2020 census.

Jupiter Island is a barrier island on the coast of Martin and Palm Beach counties, Florida. It is bounded on the east by the Atlantic Ocean, on the north by the St. Lucie Inlet, on the west by the Indian River, and on the south by the Jupiter Inlet. Jupiter Island originally was two islands, Long Island on the north and Jupiter Island on the south, which were once separated by an inlet in the vicinity of North Jupiter Narrows and what is officially called Peck Lake, but commonly called Peck's Lake.