Ephialtes (disambiguation)

Ephialtes was a fifth century BC Athenian statesman.

Ephialtes may also refer to:
 * Ephialtes, in Greek mythology, one of the twin Aloadae, possibly the same as the Giant (below)
 * Ephialtes, in Greek mythology, one of the Giants, possibly the same as the Aload (above)
 * Ephialtes (illness), name given in the 18th century to an anxiety disorder
 * Ephialtes of Trachis, betrayed the Greek army at Thermopylae to the Persians
 * Ephialtes (wasp), a genus of wasps in the family Ichneumonidae