Wernstein am Inn is a municipality in the district of Schärding, in the Austrian state of Upper Austria. It is located in the country's Innviertel region, on the river Inn that forms the border with Germany.
The community is perhaps best known for Wernstein Castle (Schloss Wernstein), which stands near the Inn and is associated with the historic crossing point over the river. The municipality comprises a number of small villages and settlements rather than a single large town.