Frohnau is a village in the Saxon town of Annaberg-Buchholz in the district of Erzgebirgskreis in southeast Germany.

The discovery of silver on the Schreckenberg led in 1496 to the foundation of the neighbouring mining town of Annaberg.

The village of Frohnau is best known for its museum of technology, the Frohnauer Hammer, and the visitor mine of Markus Röhling Stolln.

The Waldhufendorf of Frohnau is located about a kilometre west of the town centre of Annaberg.

The lower part of the village is located in the valley of the Sehma river on the Staatsstraße S261.