Cacamatzin (or Cacama) (1483–1520) was the king of Texcoco, the second most important city of the Aztec Empire.
Cacamatzin was a son of the previous king Nezahualpilli by one of his mistresses. Traditionally, the Texcocan kings were elected by the nobility from the most able of the royal family. Cacamatzin's election to the throne in 1515 was said to have been made under considerable pressure from Moctezuma II, lord of Tenochtitlán. Moctezuma II wished to lessen Texcoco's power in favor of greater centralization in Tenochtitlán.
Moctezuma II, under orders from Cortés, had Cacamatzin arrested "in his own palace while discussing war-preparations". The Caciques of Coyoacan, Iztapalapa, and Tacuba were also arrested.
Cacamatzin died during the retreat of Spanish conquistador Hernán Cortés, on the La Noche Triste.