John III, Count of Nassau-Saarbrücken (5 April 1511 – 23 November 1574) was a son of Count John Louis of Nassau-Saarbrücken and his second wife Catherine of Moers.

He succeeded his childless brother Philip II in 1554 as Count of Nassau-Saarbrücken.

He married Adelaide of Kronenkracht and Elisabeth Selz.

When he died in 1574, Nassau-Saarbrücken fell to Nassau-Weilburg.

This article about a German count is a stub.