Tetzcoco (Classical Nahuatl: Tetzco(h)co pronounced [tetsˈkoʔko], Otomi: Antamäwädehe) was a major Acolhua altepetl (city-state) in the central Mexican plateau region of Mesoamerica during the Late Postclassic period of pre-Columbian Mesoamerican chronology.

Tetzcoco was known as a center of learning within the empire, and had a famed library including books from older Mesoamerican civilizations.

The palace gardens were a vast botanical collection that included plants from not only the growing Aztec Empire but also the most remote corners of Mesoamerica.

Remnants of the gardens still exist to this day and have recently been studied by a team of Discovery Channel scientists, who were able to demonstrate by means of modeling and computer simulation that the layout of the site had been carefully planned to be in alignment with astronomical events, with an emphasis on Venus, and not simply aligned with the cardinal directions as previously assumed.

The whole hill of Tetzcotzingo was also served by this canal system and converted by his designers into a sacred place for the rain god Tláloc, complete with waterfalls, exotic animals and birds.

He was followed by Nopaltzin (1232–1263), Tlotzin (1263–1298), Quinatzin (1298–1357), Techotlalazin (1357–1409), Ixlilxochitl (1409–1418), Nezahualcoyotl (1420–1472), Nezahualpilli (1472–1516), Cacama (1517–1519), Coanchochtzin (1520–1521), and Don Fernando Ixtlilxochitl (1521–1531).

In 1520 the troops of Hernán Cortés occupied the city and killed Cacamatzin, Nezahualpilli's son and the last independent tlatoani, installing Ixtlilxochitl II as a puppet ruler.

The Tetzcoca royal family continued to rule, handling succession to the throne in accordance with the traditional Aztec patterns of legitimacy.

[4] Alva Ixtlilxochitl, the immediate Tetzcoca heir after the Spanish-Aztec War, presided over colonial Texcoco as governor until his death in approximately 1550.