Frederick I
Frederick I or Friedrich I may refer to:
- Frederick of Utrecht or Frederick I, Bishop of Utrecht.
- Frederick I, Duke of Upper Lorraine
- Frederick I, Duke of Swabia
- Frederick I, Count of Zollern
- Frederick I
- Frederick I, Holy Roman Emperor, "Frederick Barbarossa"
- Frederick I, Burgrave of Nuremberg
- Frederick I, Duke of Lorraine
- Frederick I, Count of Berg-Altena
- Frederick I, Duke of Austria , "Frederick the Catholic"
- Frederick I, Margrave of Baden
- Frederick I, Margrave of Meissen, "the Brave"
- Frederick I of Austria , "Frederick the Fair"
- Frederick I, Marquess of Saluzzo
- Frederick I, Count of Celje
- Frederick I, Duke of Athens
- Frederick I, Elector of Saxony, "the Belligerent" or "the Warlike"
- Frederick I, Elector of Brandenburg, also Burgrave of Nuremberg
- Frederick I, Count of Vaudémont
- Frederick I, Duke of Brunswick-Lüneburg
- Frederick I, Count Palatine of Simmern, "the Hunsrücker"
- Frederick I, Duke of Brunswick-Osterode
- Frederick I, Elector Palatine, "the Victorious"
- Frederick I of Mantua, Marquess of Mantua
- Frederick I of Naples, King of Naples
- Frederick I, Margrave of Brandenburg-Ansbach
- Frederick I of Denmark, King of Denmark and Norway
- Frederick I, Duke of Württemberg
- Frederick I, Landgrave of Hesse-Homburg
- Frederick I, Duke of Saxe-Gotha-Altenburg
- Frederick I of Prussia, King in Prussia
- Frederick I of Sweden, King of Sweden
- Frederick I of Württemberg, King of Württemberg
- Frederick I, Duke of Saxe-Altenburg
- Frederick I, Grand Duke of Baden
- Frederick I, Duke of Anhalt