Bianca Cappello (1548 – 20 October 1587) was an Italian noblewoman who was the mistress, and afterward the second wife, of Francesco I de' Medici, Grand Duke of Tuscany.
Her husband officially made her his consort.
Coincidentally, the creation of the fortunate term serendipity by the writer Horace Walpole is due to a portrait of Bianca.