The Temple of the Skull is named for a skull carved at the base of the central pillar

Palenque, Temple of the Skull

The Temple of the Skull may be linked to Chan Bahlam, son of Pakal the Great

The Temple of the Skull gets its name from a stucco skull located at the base of the middle pier. On close inspection, the skull can be seen in this photo at the bottom of the pier between the large rectangular doorway and the arch.

The skull for which the temple is named

The relief to which the Temple of the Skull owes it name is located at the foot of one of the pilasters on the facade. It probably represents a god of the underworld wearing ear ornaments in the shape of inverted ahau.

David Stuart has some fascinating speculation in his blog Maya Decipherment: Ideas on Ancient Maya Writing and Iconography where he pursues a link between the ruler Chan Bahlam and this temple. A wonderful read!