Mitoyo (三豊市 Mitoyo-shi) is a city located in Kagawa Prefecture, Japan.
As of 2005, the city has an estimated population of 71,178 and a population density of 320 persons per km². The total area is 222.66 km².
The modern city of Mitoyo was estblished on January 1, 2006, from the merger of all seven towns from the former Mitoyo District: Mino, Nio, Saita, Takase, Takuma, Toyonaka and Yamamoto.
Tsushima Shrine, located in Mitoyo, is only accessible one day a year in early August.
Mitoyo City has a sister city relationship with Waupaca, Wisconsin.