The Nanairo Dam (七色ダム, Nanairo-damu) is a concrete gravity-arch dam located in Kumano, Mie Prefecture, Japan. The dam crosses the Kitayama River, a tributary of the Kumano River near the border of Mie Prefecture with Wakayama Prefecture.

The dam was constructed by Obayashi Corporation, with construction starting in 1963, and completed by 1965. It is currently owned maintained by the Electric Power Development Company. The primary purpose of the dam is hydroelectric power generation, with the dam supplying the nearby Ikehara Power Plant, with an installed turbine capacity of 350 megawatts (470,000 hp). The reservoir behind the dam also serves as a pumped storage facility in conjunction with neighboring Ikehara Dam in Wakayama.