in Mesoamerican religion, Nahua sun deity of the fifth and final era (the Fifth Sun). In most myths of the Mesoamerican Nahua peoples, including those of the Aztecs (Aztec), four eras preceded the era of Tonatiuh, each ended by cataclysmic destruction. Tonatiuh, or Ollin Tonatiuh, was associated with the eagle (at sunrise and sunset) and, in Aztec versions, with the deity Huitzilopochtli.

The Aztecs viewed Tonatiuh as a god constantly threatened by the awesome tasks of his daily birth at sunrise, by his death each sunset, and by the immense effort of making his journey across the sky each day. According to Aztec traditions, the gods themselves were believed to practice voluntary sacrifice, first to create Tonatiuh and then to feed him and encourage him on his path through the sky. The worship of Tonatiuh, whose sustenance required human blood and hearts, involved militaristic cults and the practice of frequent human sacrifice to ensure perpetuation of the world.

Tonatiuh is generally represented by a colourful disk. He is best known as he is depicted in the centre of the Aztec calendar, with his eagle's claw hands clutching human hearts.