Iacopo II Appiani (1400 – December 27, 1441) was the lord of Piombino from 1405 until 1441.
He was born in Piombino, the son of Gherardo Appiano, whom he succeeded in 1405, remaining under the regency of his mother Paola Colonna until coming of age. He is described as a cruel man, switching abruptly his alliances from the Republic of Florence to that of Siena, and then moving again to the former. He strengthened his position by marrying Donella Fieschi, daughter of the powerful Genoese patrician and Florentine commander Gian Luigi Fieschi.
Iacopo died childless in 1441, perhaps poisoned, and was succeeded by his mother.