Cooper Island is a small island, 2 miles (3.2 km) long, which lies at the north side of the entrance to Drygalski Fjord, off the southeast end of South Georgia.

It was discovered by a British expedition under James Cook in 1775, and named for Lieutenant Robert Palliser Cooper, an officer aboard HMS Resolution.

A navigable channel, Cooper Sound, nearly 1 mile (1.6 km) wide, separates Cooper Island from the coast of the main island of South Georgia.

There is a small bay, Known as Cooper Bay, 1.3 miles (2.1 km) southwest of Cape Vahsel on the mainland, and 1 mile (1.6 km) northwest of Cooper Island, indenting the southeast end of South Georgia, which derives its name from Cooper Island.

As one of a handful of rat-free islands, Cooper Island is South Georgia's only Special Protection Area; it has large numbers of sea birds, including snow petrels, Antarctic prions, 12,000 pairs of black-browed albatross, chinstrap penguins, and 20,000 macaroni penguins.