Tlaloc, as depicted in the Magliabechi Codex

Tlaloc was, in Aztec mythology, the god of rain and fertility.

Tlaloc was greatly feared among the Aztecs, who sacrificed humans to him to appease him. The Aztecs believed that Tlaloc was responsible for both floods and droughts, and that Tlaloc had been created by the other gods. Tlaloc was first married to Xochiquetzal, a goddess of flowers, but then Tezcatlipoca kidnapped her. Tlaloc later married the goddess Chalchiuhtlicue, "She of the Jade Skirt". Tlaloc is commonly depicted as a blue being with fangs. His underworld included those killed by lightning, drowning and disease. With Chalchiuhtlicue, he was the father of Tecciztecatl. He had an older sister named Huixtocihuatl. Children were drowned as sacrifices to him. He ruled over the third of the five worlds in Aztec belief.

The inhabitants of Teotihuacan also worshipped Tlaloc, though not violently. In pre-Aztec times, Tlaloc was worshipped by the Teotihuacan and Toltec civilizations of Mesoamerica. Other Mesoamerican people had similar rain gods sometimes with slightly different attributes, such as the Maya rain god Chac and the Zapotec rain god Cocijo.

Alternative name: Nuhualpilli