August, Duke of Schleswig-Holstein-Sonderburg-Beck

August, Duke of Schleswig-Holstein-Sonderburg-Beck (13 February 1652 – 26 September 1689) was a Danish nobleman.

His father was the fifth son of Duke Alexander and a grandson of John II, the founder of the Schleswig-Holstein-Sonderburg line.

The Schleswig-Holstein-Sonderburg-Beck was named after Beck House, a manor in Ulenburg, which is today the smallest borough of Löhne, a town in north-eastern North Rhine-Westphalia.

Brandenburg was expanding its army and needed soldiers and officers.

In 1676, August married Hedwig Louise of Lippe-Alverdissen (1650-1731), a daughter of Count Philip I, the founder of Schaumburg-Lippe line of the House of Lippe.