Athanagild (died 567) was Visigothic King of Hispania and Septimania. He had rebelled against his predecessor, Agila, in 551. The armies of Agila and Athanagild met at Seville, where Agila met a second defeat. Following the death of Agila in 554, he was sole ruler for the rest of his reign.

Roger Collins writes that Athanagild's reign "is perhaps more significant than our sources may care to let us believe." Collins argues that the account of Isidore of Seville may be colored by the hostility subsequent Visigothic kings had towards Athanagild and his descendants.

During the conflict between the two, a Roman force sent by Justinian seized control of a large portion of Hispania Baetica (Andalusia). It is unclear what was the pretext for their arrival. Peter Heather states that Jordanes implies that Agila had summoned them. Isidore of Seville offers two conflicting stories: in the section on Agila, the Goths surrounding him killed him out of fear "that Roman soldiers might invade Spain on the pretext of giving help"; while in the following section Isidore states Athanagild had asked Justinian for his help, but once they arrived in Spain "he was unable to remove them from the territory of the kingdom despite his efforts." Collins notes that "in both of the emperor Justinian's other western interventions, Africa in 533 and Italy in 535, he came in ostensibly to uphold the rights of legitimate monarchs against usurpers", thus agreeing with Jordanes' version of the events.