Onotoa is an atoll and district of Kiribati. It is situated in the Gilbert Islands in the Pacific Ocean, from Tamana, the smallest island in the Gilberts. The population of Onotoa in the 2010 census was 1,519.
The atoll is similar to many other atolls in the Gilbert Islands with its continuous line of islets and islands on the eastern side. The western side consists of a submerged reef which surrounds the islet filled lagoon.