Hermann I, Count of Celje

Hermann I (c. 1333–1385), Count of Celje, was the second son of Frederick I and Diemut of Wallsee. From his father's death in 1359 he ruled jointly with his elder brother Ulrich I, and alone after Ulrich's death in 1368, guarding the inheritance of his young nephew William.

His marriage to Catherine Kotromanić of Bosnia linked the counts of Celje to the Hungarian and Bosnian royal houses. He died in 1385, the greatest landowner in Slovenia, succeeded by his son Hermann II.