This article is on the first Duke of Florence. For the Alessandro de' Medici who was pope, see Pope Leo XI.

Alessandro de' Medici (July 22, 1510 – January 6, 1537) called "il Moro" ("the Moor"), Duke of Penne and also Duke of Florence (from 1532), was ruler of Florence from 1530 until 1537. Though illegitimate, he was the last member of the "senior" branch of the Medici to rule Florence and the first to be a hereditary duke.