Piero di Cosimo (also known as Piero di Lorenzo) (1462–1521) was an Italian painter. The son of a Florentine goldsmith, he apprenticed under Cosimo Rosseli , whom he assisted in the decoration of the Sistine Chapel. He was noted for his rather eccentric personality and unorthodox interpretations of mythological subjects. He also wrote a relatively famous treatise on geometry. Piero's students included Andrea del Sarto. He was found dead at the foot of a flight of stairs.

His works include:

• Portrait of Simonetta Vespucci (c. 1480)
• The Visitation with Saint Nicholas and Saint Anthony Abbot (c.1490) painted as an altarpiece for the Capponi chapel in the church of Santo Spirito, Florence
• A Satyr mourning over a Nymph (c.1495)
• The Discovery of Honey by Bacchus (c.1499)
• Allegory (c. 1500) (oil on panel)
• The Nativity with the Infant Saint John (c. 1500) (oil on canvas)
• The Fight between the Lapiths and the Centaurs (c.1500-15)
• La Maddalena (1501)
• The Return from the Hunt (c.1505–7)
• Perseus Frees Andromeda (c.1513) (oil on wood)
• The Building of a Palace (c.1515/20) (Oil on panel)
• Frescoes in the Sistine Chapel of Moses and the Tables of Law and Sermon on the Mount and Healing of the Leper.

Giorgio Vasari includes a biography of Piero di Cosimo in his Lives of the Artists.