Alastaro is a municipality of Finland.

It is located in the province of Southern Finland and is part of the Varsinais-Suomi region. The municipality has a population of 3076 and covers an area of 259,94 kmē of which 0,98 kmē is water. The population density is 11,781 inhabitants per kmē.

The municipality is unilingually Finnish.

See also: Municipalities of Southern Finland