Harald Wartooth or Harold Hiltertooth was a semi-legendary king of Denmark who is mentioned in several traditional sources. He is held to have (indirectly) succeeded his father as king of Zealand and to have expanded his realm. According to different sources, he may have ruled over Jutland, part of Sweden and the historical northern German province of Wendland. He is said to have been finally defeated and killed at the legendary Battle of Bråvalla.

The Battle of Brávellir or the Battle of Bråvalla was a legendary battle, said to have taken place c. 770, that is described in the sagas as taking place on the Brávellir between Sigurd Hring, king of Sweden and the Geats of Västergötland, and his uncle Harald Wartooth, king of Denmark and the Geats of Östergötland.