Gwynn's Island is an island in the Chesapeake Bay and the U.S. state of Virginia, lying off of the Middle Peninsula. A summer colony, the island is located in the northeast part of Mathews County, south of the mouth of the Piankatank River. It is connected to the rest of the county by a swing bridge over Milford Haven. The communities of Gwynn and Grimstead are located on the island.

Archeological evidence found on Gwynn's Island indicates that the island was inhabited as early as ten thousand years ago. In 1642, Hugh Gwynn of Jamestown purchased the island; he and his family became the first English settlers there. On a 1670 map, the island was labeled "Wings Ile" and also "Guis Ile". In 1776, Gwynn's Island served as a base for Lord Dunmore, the last royal governor of Virginia, after the Burning of Norfolk. A smallpox outbreak and attacks by the revolting patriots led Dunmore to leave the island in the summer of 1776.

During the attacks on Gwynn's Island in July 1776, the only casualty on the side of the revolutionaries was one Captain Dohickey Arundel, commander of two eighteen-pound cannons, who attempted to fire an experimental wooden mortar of his own invention, "though the general and all the officers were against his firing it". The mortar exploded on its first shot, killing Arundel instantly.

Thomas Edwards, a resident of the Island, is the Director of the Gwynn's Island Museum and has been at the helm since 2015.

• Gwynn's Island Museum
• Gwynn's Island Festival