Yagul is an archaeological site and former city-state associated with the Zapotec civilization of pre-Columbian Mesoamerica, located in the Mexican state of Oaxaca. The site was declared one of the country's four Natural Monuments on 13 October 1998. The site is also known locally as Pueblo Viejo and was occupied at the time of the Spanish Conquest. After the Conquest the population was relocated to the nearby modern town of Tlacolula where their descendants still live.
Yagul was first occupied around 500-100 BC. Around 500-700 AD, residential, civic and ceremonial structures were built at the site. However, most of the visible remains date to 1250-1521 AD, when the site functioned as the capital of a Postclassic city-state.
The site was excavated in the 1950s and 60s by archaeologists Ignacio Bernal and John Paddock.
Vestiges of human habitation in the area, namely cliff paintings at Caballito Blanco, date to at least 3000 BC. After the abandonment of Monte Albán about 800 AD, the region's inhabitants established themselves in various small centers such as Lambityeco, Mitla and Yagul.