| Frederick William III, Duke of Schleswig-Holstein-Sonderburg-Beck | |
|---|---|
| Born | 4 November 1723 |
| Died | 6 May 1757 (aged 33) Prague |
| Noble family | House of Oldenburg |
| Father | Frederick William II, Duke of Schleswig-Holstein-Sonderburg-Beck |
| Mother | Ursula Anna of Dohna-Schlodien |
Frederick William III, Duke of Schleswig-Holstein-Sonderburg-Beck (4 November 1723 – 6 May 1757) was a son of Frederick William II and his wife, Ursula Anna of Dohna. He succeeded his father as Duke of Beck in 1749.
Frederick William was a recipient of the Order of the Red Eagle. He served as a colonel in the Prussian Army and was commander of the Füsilier Regiments No. 46 (Old-Württemberg). During the Seven Years' War, he fell in the Battle of Prague in 1757. He was unmarried and childless; he was succeed as Duke of Beck by his uncle Charles Louis.