The Massacre in the Great Temple of the Aztec capital Tenochtitlan is an episode in the Spanish conquest of Mexico that begins on May 20, 1520.While Hernán Cortésis in Tenochtitlan, he hears about other Spaniards arriving on the coast—Pánfilo de Narváez had come from Cuba with orders to arrest him—and Cortés is forced to leave the city to fight them.

During his absence, Moctezuma ass deputy governor Pedro de Alvarado for permission to celebrate Toxcatl (an Aztec festivity in honor of Tezcatlipoca, one of their main gods).

After the festivities had started, however, Alvarado interrupts the celebration, killing almost everyone present at the festival, men, women, and children alike.

The Spanish version of the incident claims the conquistadors intervened to prevent a ritual of human sacrifice in the Templo Mayor; the Aztec version says the Spaniards were enticed into action by the gold the Aztecs were wearing, prompting an Aztec rebellion against the orders of Moctezuma.

While differing so on Alvarado's specific motive, both accounts are in basic agreement that the celebrants were unarmed and that the massacre was without warning and unprovoked.