Thyra or Thyri (Old Norse: Þyri or Þyre) was the wife of King Gorm the Old of Denmark, and one of the first queens of Denmark believed by scholars to be historical rather than legendary. She is presented in medieval sources as a wise and powerful woman who ordered the building or fortification of the Danevirke, consistent with her commemoration on multiple Viking Age runestones. These include those at Jelling which was the seat of power for her dynasty.
Although her existence is documented in Viking Age runic inscriptions, very little is known about Thyra with certainty as no other contemporary sources about her survive. Much of her story is pieced together through 12th and 13th century sources that broadly disagree with one another, such as Icelandic sagas and writings of the medieval historians Saxo Grammaticus and Sven Aggesen. When she was born and became queen is unclear, however, she likely ruled until her death in the middle of the 10th century. Historians widely agree that she and Gorm were the parents of Harald Bluetooth and likely also Canute. The Historia Norwegiæ additionally claims that they had a daughter, Gunnhild, Mother of Kings, though this is less certain.
