San Lorenzo Tenochtitlán or San Lorenzo is the collective name for three related archaeological sites—San Lorenzo, Tenochtitlán and Potrero Nuevo—located in the southeast portion of the Mexican state of Veracruz. Along with La Venta and Tres Zapotes, it was one of the three major cities of the Olmec, and the major center of Olmec culture from 1400 BCE to 900 BCE. San Lorenzo Tenochtitlán is best known today for the colossal stone heads unearthed there, the greatest of which weigh 28 metric tons (28 long tons; 31 short tons) or more and are 3 metres (9.8 ft) high.

The site should not be confused with Tenochtitlan, the Aztec site in Mexico City. Administrative names were translated into Aztec/Nahuatl and spread alongside Catholic names during the European conquest, replacing any original locality names, as the original Olmec name was lost.