Pantaleon is a Greek king who reigned some time between 190–180 BCE in Bactria and India.

He is a younger contemporary or successor of the Greco-Bactrian king Demetrius, and is sometimes believed to have been his brother and/or subking.

He is the first Greek king to strike Indian coins, peculiar irregular bronzes which suggests he had his base in Arachosia and Gandhara and wanted support from the native population.