Pantaleon was a Greek king who reigned some time between 190 and 180 BC in Bactria and India. He was a younger contemporary or successor of the Greco-Bactrian king Demetrius, and is sometimes believed to have been his brother and/or subking.
The scarcity of his coinage indicates a short reign. Known evidence suggests that he was replaced by his (probable) brother or son Agathocles, by whom he was commemorated on a "pedigree" coin.