Prince Karl Anton August of Schleswig-Holstein-Sonderburg-Beck (10 August 1727, in Marburg12 September 1759, in Stettin) was the son of Peter August, Duke of Schleswig-Holstein-Sonderburg-Beck and Princess Sophie of Hesse-Philippsthal.
Marriage and issue
On 30 May 1754, Anton (as he was known) married Countess Frederica Charlotte of Dohna-Schlodien in Leistenau in Königsberg. The couple had one child, Friedrich Karl Ludwig, Duke of Schleswig-Holstein-Sonderburg-Beck.
Anton would have inherited the dukedom of Schleswig-Holstein-Sonderburg-Beck had it not been for his early death by wounds suffered at the Battle of Kunersdorf, where he had fought as a major in the Prussian Army. His father Peter outlived him, so the dukedom was passed on from Peter to Anton's only son, Friedrich.