Beatriz Pereira de Alvim

Beatriz Pereira de Alvim (1380–1414) was a Portuguese noblewoman, the only child of Nuno Álvares Pereira and his wife Leonor de Alvim.

On 8 November 1401, she married Afonso, Count of Barcelos, illegitimate son of king John I of Portugal. She died before her husband became Duke of Braganza.

Afonso and Beatriz had three children.
 * Afonso of Braganza (1400–1460), 4th Count of Ourém and 1st Marquis of Valença, had a natural son from Dona Brites de Sousa (some say they secretly married). His issue took the name de Portugal
 * Isabella of Braganza (1402–1465), married her uncle Infante John, Lord of Reguengos, son of John I of Portugal
 * Ferdinand I, Duke of Braganza (1403–1478), succeeded his father as second Duke of Braganza