Mastník is a municipality and village in Třebíč District in the Vysočina Region of the Czech Republic.

Mastník is located about 5 kilometres (3 mi) southwest of Třebíč and 29 km (18 mi) southeast of Jihlava.

It lies in the Jevišovice Uplands.

The highest point is the hill Pekelný kopec at 572 m (1,877 ft) above sea level.

This Vysočina Region location article is a stub.