Tlacolula de Matamoros is a city and municipality in the Mexican state of Oaxaca, about 30 km from the center of the city of Oaxaca on Federal Highway 190, which leads east to Mitla and the Isthmus of Tehuantepec.
It is part of the Tlacolula District in the east of the Valles Centrales Region.
The city is the main commercial center for the Tlacolula Valley area, and best known for its weekly open air market held on Sundays. This market is one of the oldest, largest and busiest in Oaxaca, mostly selling food and other necessities for the many rural people which come into town on this day to shop. The city is also home to a 16th-century Dominican church, whose chapel, the Capilla del Señor de Tlacolula, is known for its ornate Baroque decoration and a crucifix to which have been ascribed many miracles. Outside the city proper, the municipality is home to the Yagul archeological site. and a number of a group of one hundred caves and rock shelters which document the pre-historic transition of people from hunting and gathering to agriculture based on the domestication of corn and other plants.