Henry the Lion (German:Heinrich der Löwe; 1129/1131 – 6 August 1195) was a member of the Welf dynasty and Duke of Saxony, as Henry III, from 1142, and Duke of Bavaria, as Henry XII, from 1156, which duchies he held until 1180.

He was one of the most powerful German princes of his time, until the rival Hohenstaufen dynasty succeeded in isolating him and eventually deprived him of his duchies of Bavaria and Saxony during the reign of his cousin Frederick I Barbarossa and of Frederick's son and successor Henry VI.