Ernest August, Duke of Schleswig-Holstein-Sonderburg-Augustenburg
Born(1660-10-30)30 October 1660
Died12 March 1731(1731-03-12) (aged 70)
Noble familyHouse of Oldenburg
Spouse(s)Maria Theresia of Weinberg
FatherErnest Günther, Duke of Schleswig-Holstein-Sonderburg-Augustenburg
MotherAuguste of Schleswig-Holstein-Sonderburg-Glücksburg

Ernest August, Duke of Schleswig-Holstein-Sonderburg-Augustenburg (30 October 1660 – 12 March 1731) was the second son of Duke Ernest Günther and his wife Auguste.

Ernest August converted to Catholicism and became a canon in Strasbourg. However, he later reverted to Lutheranism.

In 1692, he succeeded his childless brother Frederick as Duke of Augustenburg. In 1695 he married Baroness Maria Theresia of Weinberg. This marriage remained childless.

Ernest August, Duke of Schleswig-Holstein-Sonderburg-Augustenburg House of OldenburgBorn: 30 October 1660 Died: 12 March 1731 Preceded byFrederick Duke of Schleswig-Holstein-Sonderburg-Augustenburg 1692–1731 Succeeded byChristian August