The Great Nicobar Biosphere Reserve is a vast and ecologically significant area located on the island of Great Nicobar, the southernmost island in the Nicobar group of the Andaman and Nicobar Islands.

Established in 2013, the reserve covers an area of 103,870 hectares, with a core area of 53,623 hectares that includes Campbell Bay National Park and Galathea National Park. The reserve is known for its rich biodiversity, encompassing tropical wet evergreen forests, mountain ranges, and coastal plains.

It is home to over 1,800 species of plants and animals, including many endemic and endangered species. Some notable species include the Nicobar scrubfowl, edible-nest swiftlet, Nicobar long-tailed macaque, saltwater crocodile, giant leatherback sea turtle, and the giant robber crab.

The Great Nicobar Biosphere Reserve also supports the indigenous Nicobarese and Shompen tribes, who have lived in harmony with the island's natural environment for generations. The reserve plays a crucial role in promoting sustainable development and conservation efforts in the region.