Georgian Bay Islands National Park consists of 59 small islands or parts of islands in Georgian Bay, near Port Severn, Ontario. The park was established in 1929. The total park area is approximately 12 km².

The islands blend the exposed rocks and pines of the Canadian Shield with the hardwood forests found further south. The park can only be reached by boat; there are limited camping facilities and a visitor centre on the largest island, Beausoleil Island.

The park provides habitat for 33 species of reptiles and amphibians, including the threatened eastern Massasauga Rattlesnake . Some of the more isolated islands provide nesting areas for colonies of gulls and terns. Black Terns can be found nesting on some islands here.

The park is part of the Georgian Bay Littoral Biosphere Reserve.