Seymour Island usually refers to an island off the tip of the Graham Land in Antarctica. 

Seymour Island may also refer to:

 Seymour Island (Nunavut), an uninhabited island in the Qikiqtaaluk Region of northern Canada's territory of Nunavut
 North Seymour Island, formerly Seymour Island, an uninhabited island in the Galápagos Islands in Ecuador
 Baltra Island, formerly South Seymour Island, a small island in the Galápagos Islands in Ecuador
 Seymour Airport, formerly Seymour Island Airfield, an airport on Baltra
 Seymour Island in Billington Sea, Plymouth, Massachusetts, U.S.A.
 Seymour Island in Doubtful Sound, South Island, New Zealand