Thundorf (in the local dialect [ˈtuəndɔrfː] or [ˈtuəndərəfː]) is a municipality in the district of district of Frauenfeld in the canton of Thurgau in Switzerland.
The village of Thundorf lies on a plateau above Frauenfeld. In 1995, the communal territory was enlarged to the east, when Wetzikon and Lustdorf, the latter of which until then was autonomous, were joined to it.