Cacamatzin (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 nobilty 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, who wished to lessen Texcoco's power in favor of greater centralization in Tenochtitlán.

Cacamatzin was killed by strangling by soldiers of Spanish conquistador Hernán Cortés, who some sources say were torturing him in an effort to get gold.

Under the direction of Cortés, Cacamatzin's half brother Ixtlilxochitl II was baptized as a Christian with the new name Fernando and appointed the new king of Texcoco.