Frederick III
Frederick III may refer to:
- Frederick III, Duke of Upper Lorraine
- Frederick III, Duke of Swabia
- Friedrich III, Burgrave of Nuremberg
- Frederick III, Duke of Lorraine
- Frederick III of Sicily, also known as Frederick II of Sicily
- Frederick III of Germany, nicknamed the Fair, King of the Romans and previously Duke Frederick I of Austria
- Frederick III, Margrave of Baden-Baden
- Frederick III, Landgrave of Thuringia
- Frederick III, Margrave of Meissen
- Frederick III the Simple, King of Sicily
- Frederick III, Duke of Austria
- Frederick III, Count of Moers
- Frederick III, Count of Veldenz
- Frederick III, Holy Roman Emperor
- Frederick III, Duke of Brunswick-Lüneburg
- Frederick III, Elector of Saxony, also known as Frederick the Wise
- Frederick III, Elector Palatine
- Frederick III, Duke of Legnica
- Frederick III, Duke of Holstein-Gottorp
- Frederick III of Denmark
- Frederick III, Margrave of Brandenburg-Ansbach
- Frederick III of Brandenburg, also Frederick I of Prussia, Elector of Brandenburg
- Frederick III, Landgrave of Hesse-Homburg
- Frederick III, Duke of Saxe-Gotha-Altenburg
- Frederick Philipse III
- Frederick III, Prince of Salm-Kyrburg
- Friedrich III, Landgrave of Hesse-Cassel
- Frederick III, Duke of Wurttemberg
- Frederick III, German Emperor