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