A tecoatl (plural tecoatles) is a stone canal making up part of an extensive ancient aqueduct network in the Tehuacán Valley in the state of Puebla in Mexico. The word tecoatl translates to "stone snake" in the Aztec language Nahuatl, but the canal system is far older than the Aztecs. The first segments of the system were laid down approximately 2500 years ago.
Archaeological investigation of the tecoatl system began in the late 1960s, and further studies revealed that the tecoatles make up the longest prehistoric irrigation system in the New World. At one point 1200 kilometers of stone canals provided water to 330 km² of cultivated land in the Tehuacán Valley.