Tarvasjoki () is a former municipality in the region of Southwest Finland, in Finland. It was merged with the municipality of Lieto on 1 January 2015.
The municipality had a population of 1,959 (30 November 2014)
Villages
Eura, Horrinen, Hungerla, Jauhola, Juva, Kallela, Karhula, Killala, Kirkonkylä, Kättylä, Liedonperä, Mäentaka, Satopää, Seppälä, Suitsula, Suurila, Takamaa, Tiensuu, Tuomarla, Tuorila, Tyllilä, Yrjönkylä.
Famous people from Tarvasjoki
- Gustaf Mauritz Armfelt, (1757 in Juva, Tarvasjoki – 1814) a Finnish-Swedish-Russian courtier and diplomat.