Semiramide Appiano of Aragon (1464 – 9 March 1523) was an Italian noblewoman, daughter of the Lord of Piombino Jacopo III Appiano and wife of Lorenzo di Pierfrancesco de' Medici.

She was the niece of the famous Simonetta Vespucci, Botticelli's muse and Giuliano de' Medici's beloved.

She was the daughter of Jacopo III Appiano, Lord of Piombino and relative of the Aragonas of Naples (his mother was Colia de' Giudici, natural daughter of Alfonso V of Aragon), and of Battistina Fregoso,[2][3] daughter of Genoa doge Battista Fregoso, sister of doge Pietro Fregoso and maternal half-sister of the famous Simonetta Vespucci, known for her beauty and alleged lover of Giuliano de' Medici.

[1] In 1478 Lorenzo de' Medici, Giuliano's older brother and Lord of Florence, arranged a betrothal between Giuliano and Semiramide, but the marriage was never held due to Giuliano's death on 26 April 1478 during the Pazzi conspiracy.

[2][4] Semiramide died in Florence on 9 March 1523 at fifty-eight age.