The Hárbarðsljóð (also spelt Harbarthsljoth and variations on this) is a flyting poem of Norse mythology. It is to be found in the Codex Regius.

In the conventional interpretation of this poem the deities Odin and Thor compete with each other. Odin, disguised (as usual!) as Hárbarð (meaning "Greybeard"), a ferry man, is rude and obnoxious towards Thor who is returning to Asgard after a journey in Jotunheim, the land of the giants. Hárbarð boasts of his sexual prowess, his magical powers and his tactical abilities. Thor then tells of how the giants were defeated by him.

In this take on Hárbarðsljóð, the poem appears to draw a stark contrast between two of the principal gods of the Nordic cosmogony; Odin, the cunning warmonger, Thor, the protector of mortals against the ravages of the giants.

Some commentators, however, argue (not unreasonably) that there is doubt to be cast on assigning the persona of Odin to Harbard; many of the characteristics of Harbard are more akin to those of Loki than to Odin. For example, throughout the entirety of Hárbarðsljóð, Harbard boasts of his prowess among women, as does Loki in Lokasenna. Coincidentally, both Lokasenna and Hárbarðsljóð also accuse Thor's wife Sif of adultery.

Poetically, it is significantly less structured than most Eddic poems, and is predominantly written in a style known as Malahattr or "conversational style". However, other metrical forms are also to be discerned, while some of the stanzas are pure prose. The generally held opinion amongst scholars of Old Norse is that the poem was consigned to paper in the late 11th century.