Juan Velázquez Tlacotzin was an Aztec leader in Tenochtitlan, during the final decades of the Aztec Empire. He then was the first post-Spanish conquest Tlatoani (Aztec ruler) from 1525 to 1526.
Tlacotzin was grandchild of the Cihuacoatl Tlacaeleltzin. He was a Cihuacoatl (counselor) during the rule of Moctezuma II and of Cuauhtémoc.
Tlacotzin was captured and later tortured by Hernán Cortés, along with Cuauhtémoc, to reveal the location of Royal Treasures and gold of the Imperial Family.
After the execution of Emperor Cuauhtémoc he was chosen as the Cuauhtemoc's successor. Immediately after the execution of Cuauhtemoc, Cortés ordered Tlacotzin be dressed as a Spaniard, given a sword and a white horse as symbols of his new position as Tlatoani. Tlacotzin was also baptized by the Spanish as don Juan Velásquez.
He accompanied Cortés on his three year expedition, but died in 1526 (8 Tochtli) while on it, of an unknown sickness in Nochixtlan. Cortés immediately chose Andrés de Tapia Motelchiuh as his successor.