Ōtoyo is a town located in Nagaoka District, Kōchi Prefecture, Japan. As of 1 August 2022, the town had an estimated population of 3277 in 1968 households and a population density of 10 persons per km². The total area of the town is 315.06 square kilometres (121.65 sq mi).

Kōchi Prefecture is a prefecture of Japan located on the island of Shikoku. Kōchi Prefecture has a population of 669,516 and has a geographic area of 7,103 km2. Kōchi Prefecture borders Ehime Prefecture to the northwest and Tokushima Prefecture to the northeast.