Seranishi (世羅西町; -cho) was a town located in Sera District, Hiroshima, Japan.
On October 1, 2004 Seranishi, along with the town of Kōzan, also from Sera District, was merged into the expanded town of Sera and no longer exists as an independent municipality.
As of 2003, the town had an estimated population of 3,919 and a density of 56.68 persons per km². The total area was 69.14 km².