Erymanthos () is a municipality in Achaea, Western Greece. The seat of the municipality is the town Chalandritsa. The municipality has an area of 582.139 km<sup>2</sup>. It was named after Mount Erymanthos.
The municipality Erymanthos was formed at the 1/1/2011 local government reform by the merger of the following 4 former municipalities and communities, that became municipal units: