Beatrice of Castile or Beatriz was an infanta of Castile, daughter of Sancho IV and María de Molina. She was Queen of Portugal from the accession of her husband, Afonso IV, in 1325 until his death on 28 May 1357.

Sancho IV of Castile called the Brave, was the king of Castile, León and Galicia from 1284 to his death. Following his brother Ferdinand's death, he gained the support of nobles that declared him king instead of Ferdinand's son Alfonso. Faced with revolts throughout his reign, before he died he made his wife regent for his son Ferdinand IV.