Halga, Helgi, Helghe or Helgo was a legendary Danish king living in the early 6th century. His name would in his own language (Proto-Norse) have been *Hailaga (dedicated to the gods).

Scholars generally agree that he appears in both Anglo-Saxon (Beowulf) and Scandinavian tradition (Norse sagas and Danish chronicles). In both traditions, he was a Scylding, the son of Healfdene and the brother of Hroðgar. In Beowulf, his relationship to Hroðulf is not explained, but if he was not his father, as in the Scandinavian tradition, he was at least his uncle. Both traditions also mention his family's feud with Froda and Ingeld.

Whereas, not much is said about Halga in Anglo-Saxon sources, much more is said in Scandinavian ones. It is also noticed a curb in Halga storyline's direction, all of them containing a version of the story of his incestuous relationship with his own daughter Yrsa. This liaison resulted in Halga's son Hroðulf.

In the Anglo-Saxon epic Beowulf, Halga is hardly mentioned. He appears early in the poem where he is listed as the brave Halga, one of the four children of Healfdene, the others being Heorogar, Hroðgar and a daughter (who is unnamed, but called Signý in Norse sources) who was married to the king of Sweden.

59  Ðæm feower bearn    forðgerimed

60  in worold wocun    weoroda ræswa
61  heorogar. 7 hroðgar    7 halga til
62  hyrde ic þ    elan cwen

63  heaðo-Scilfingas    healsgebedda

This appears in Gummere's translation as: