Masonboro Island is a barrier island in New Hanover County, North Carolina, United States.

The island, which is undeveloped and accessible only by boat, is a component of the North Carolina National Estuarine Research Reserve and a North Carolina State Natural Area.

The island is a destination for boating, surfing, and camping.

Masonboro Island is a mix of marshes, dunes and tidal flats, with beaches along its Atlantic coastline and a chain of small hills and wetland islands along Masonboro Sound, which is part of the Intracoastal Waterway.

The beaches are a nesting ground for loggerheads and green sea turtles, and the waters on the sound side of the island are a nursery for spot, mullet, flounder and pompano.