Halikko is a former municipality in the Southwest Finland region of Finland. It existed as an independent municipality until December 31, 2008, when it was merged into the larger neighbouring town of Salo on January 1, 2009. Since that date it has formed part of Salo rather than functioning as a separate administrative unit.
Before the merger, Halikko had developed into a rapidly urbanizing rural area, a settlement pattern in which a traditionally rural locality takes on increasing urban characteristics. The municipality was located in the south-western part of the country, within the region of Southwest Finland.
Its administrative history is the feature most commonly associated with Halikko: a long-standing rural municipality that was absorbed by its larger neighbour at the beginning of 2009. The area is now part of Salo, and no separate municipal institutions remain.