Margareta Eriksdotter Vasa (1497 – 31 December 1536), also called Margareta Vasa and Margareta of Hoya, was a Swedish noblewoman, sister of king Gustav I of Sweden.
Margareta was born to Erik Johansson Vasa and Cecilia Månsdotter and thus sister to the future king Gustav Vasa. Nothing is known of her childhood, but it is known that she could speak both Swedish and German, that she could read and write (which was not a given thing even by members of the nobility in this period) and that she had a great interest in literature: she placed her own daughters in school at Sko Abbey at the age of five, and it is considered likely that she was herself also spent a period at convent school, which was at the time customary within the Swedish nobility.
On 30 March 1516, she married riksråd Joakim Brahe at Tre Kronor (castle) in a wedding hosted by the Swedish regent Sten Sture the Younger: her spouse was a loyal follower of Sture, and the regent was married to her aunt, Christina Gyllenstierna.
In November 1520, Margareta and her spouse attended the coronation of Christian II of Denmark as king of Sweden. Her spouse and father belonged to those executed at the . Margareta and her children, along with her mother, sister Emerentia, grandmother Sigrid Eskilsdotter (Banér) and aunt Christina Gyllenstierna, belonged to the women and children related to the executed that were imprisoned at Stockholm Castle and then transferred to the infamous Blåtårn ("Blue Tower") of Copenhagen Castle the following summer.
In the chronicle of her son Per Brahe the Elder (who was with her during the captivity) the captivity of the Swedish noblewomen in Denmark were described: "They were much deprived of food and drink [...]. Hardly given enough each day to keep their lives but they worked to be fed": king Gustav I of Sweden used their treatment in captivity in his propaganda against Christian II and claimed that the Danish monarch starved the women and children who only survived by the mercy showed them by the queen of Denmark, Isabella of Austria. Whatever the truth of this, it is confirmed that many of the imprisoned women and children died, among them Margareta's mother Cecilia, sister Emerentia and cousin Magdalena, though the cause of death are given as the plague, at that point used to classify a number of different illnesses.