Blanche of Portugal (25 February 1259 in Santarém, – 17 April 1321 in Burgos; Branca Portuguese pronunciation: ['b??~k?] in Portuguese and Blanca in Spanish), was an infanta, the firstborn child of King Afonso III of Portugal and his second wife Beatrice of Castile.
Named after her great-aunt Blanche of Castile, queen of France, Blanche was the Lady of Las Huelgas, Montemor-o-Velho, Alcocer and Briviesca, the city which she founded.