The Asgard are an alien race from the Stargate Universe. They were a benevolent, extremely advanced race from the Ida galaxy that visited Earth on many occasions. They used the cover of primitive gods in a similar manner to the Goa'uld, leading to the development of Nordic mythology.
Part of the Alliance of Four Great Races, they were among the most advanced races in the universe, matched only by the Ancients, the Nox, and possibly the Furlings. They assumed the role of protectors of the Milky Way galaxy and later passed that role down to the Tau'ri, to whom they gifted all of their knowledge and technology.