was a town located in Kaisà  District, Wakayama Prefecture, Japan.
As of 2003, the town had an estimated population of 14,481 and a density of 363.57 persons per km<sup>2</sup>. The total area was 39.83 km<sup>2</sup>.
On April 1, 2005, Shimotsu was merged into the expanded city of Kainan.