Frederick William III (disambiguation)

Frederick William III of Prussia (1770–1840) was king of Prussia from 1797 to 1840.

Frederick William III or Friedrich Wilhelm III may also refer to:


 * Friedrich Wilhelm III, Duke of Saxe-Altenburg (1657–1672)
 * Frederick William III, Duke of Schleswig-Holstein-Sonderburg-Beck (1723–1757)
 * Frederick William III, Landgrave of Hesse (1854–1888), titular Landgrave of Hesse-Kassel