Niedermayrite is a rare hydrated copper cadmium sulfate hydroxide mineral with formula: Cu4Cd(SO4)2(OH)6·4H2O.

Niedermayrite was named for Gerhard Niedermayr (born 1941), an Austrian mineralogist.

It was first described in 1998 from a mine in the Lavrion District, Attica, Greece.

It is also reported from the Ophir District, Tooele County, Utah.

This article about a specific sulfate mineral is a stub.