Gostynin [ɡɔsˈtɨɲin] is a town in Central Poland with 19,414 inhabitants (2004). It is situated in the Masovian Voivodship since 1999 and was previously in the Płock Voivodship from 1975 to 1998. It is the capital of Gostynin County.

Gostynin has a long and rich history, which dates back to the early Middle Ages. In the 6th century, a Slavic gord existed north of contemporary town, on a hill located on the left bank of the Skrwa Lewa river, along a merchant trail. In the 12th century, the settlement found itself near the border between the provinces of Mazovia and Kujawy.