Starbuck Island, also known as Volunteer Island, is an uninhabited coral atoll in the central Pacific Ocean, part of the Southern Line Islands belonging to Kiribati.

Located at , and measuring 8.9 km east-to-west and 3.5 km north-to-south, Starbuck Island was first sighted in 1823 by Valentine Starbuck , master of a British whaling ship. Claimed by the United States under the 1856 Guano Act, but controlled by the British after 1866, Starbuck Island was mined for phosphate between 1870 and 1893. Because of its low profile (at its highest point, the island rises to about 5 meters) and dangerous surrounding reef, a number of ships wrecked at Starbuck Island in the late 1800s.

Starbuck Island has been designated a protected area by the United Nations and is home to a colony of Sooty Terns .

The island has also been known under the names of Low, Starve, Hero, Barren and Coral Queen.

Starbuck Island is also the name of an island in the Hudson River between Troy, NY and Watervliet, NY .