The Duchy of Saxe-Wittenberg (German: Herzogtum Sachsen-Wittenberg) is a medieval duchy of the Holy Roman Empire centered at Wittenberg, which emerges after the dissolution of the stem duchy of Saxony.

The Ascanian dukes prevail in obtaining the Saxon electoral dignity until their duchy is finally elevated to the Electorate of Saxony by the Golden Bull of 1356.