|terrain = [[Region:Lounais-Suomi|Lounais-Suomi]]

'''Siikainen''' (swedish Siikais) is a municipality in the region of [[Region:Lounais-Suomi|Lounais-Suomi]]. It is located in the former province of Western Finland and is part of the [[Satakunta]] region. The municipality has a population of 1,454 (31 January 2019) and the municipality covers an area of 491.33 square kilometres (189.70 sq mi) of which 28.10 square kilometres (10.85 sq mi) is inland water (2018-01-01). The population density is 3 inhabitants per square kilometre (7.8/sq mi) (31 January 2019).