Idiorophus is a genus of extinct toothed whales in the family Physeteridae. Fossils have been found in the Colhuehuapian Gaiman Formation of Argentina and the Libano Sandstone in Italy.
Idirophus is thought to have been long. Discovered in rocks dated to the early Miocene, it is thought to be one of the oldest sperm whales. The teeth of Idiorophus were similar in size to those of the modern orca. This species is thought to be a highly predatory sperm whale. The teeth are covered in enamel and show wear from eating large prey.
It has been proposed that Idiorophus be placed in the subfamily Hoplocetinae, alongside Scaldicetus, Diaphorocetus, and Hoplocetus.