Setouchi is a city located in southern Okayama Prefecture, Japan.
As of March 1, 2017, the city had an estimated population of 37,934, with 15,396 households and a population density of 300 persons per km². The total area is 125.51 km².
The modern city of Setouchi was founded on November 1, 2004, by the merger of the former towns of Oku, Osafune and Ushimado. Its city hall is the former town hall of Oku.
The name Setouchi is derived from Seto Inland Sea. The city faces the Inland Sea on its eastern and southern parts. The climate is moderate. Its main industries are fishery, agriculture, pottery, and sightseeing.