Ban Chiang (Thai: บ้านเชียง, pronounced [bâːn tɕʰīaŋ] listen^ⓘ; Northeastern Thai: บ้านเซียง, pronounced [bâːn sîaŋ]) is an archaeological site in Nong Han district, Udon Thani province, Thailand. It has been a UNESCO World Heritage Site since 1992. Discovered in 1966, the site first attracted interest due to its ancient red-painted pottery. More recently, it gained international attention in 2008 when the United States Department of Justice, following an undercover investigation begun in 2003, raided several museums for their role in trafficking in Ban Chiang antiquities.

Villagers had uncovered some of the pottery in prior years without insight into their age or historical importance. In August 1966, Steve Young, a political science student at Harvard College, was living in the village conducting interviews for his senior honors thesis. Young, a speaker of Thai, was familiar with the work of Wilhelm Solheim and his theory of the possible ancient origins of civilization in Southeast Asia. One day while walking down a path in Ban Chiang with his assistant, an art teacher at the village school, Young tripped over the root of a red kapok tree (Bombax ceiba) and fell on his face in the dirt path. Under him were the exposed tops of small and medium-sized pottery jars. Young recognized that the unglazed earthenware pots had been low-fired and were quite old, but that the designs applied to the surface of the vessels were unique. He took samples of pots to Princess Phanthip Chumbote at the private museum of Suan Pakkad Palace in Bangkok and to Chin Yu Di of the Thai Government's Fine Arts Department. Later, Elisabeth Lyons, an art historian on the staff of the Ford Foundation, sent potsherds from Ban Chiang to the University of Pennsylvania for dating. Unfortunately, the early publicity, the beauty of the pots, and the belief that the pots were several thousands of years old led to avid collecting and consequent avid looting by the villagers.

The Fine Arts Department of Thailand conducted several small excavations during the 1960s and early 1970s. These excavations revealed skeletons, bronze artifacts and a wealth of pots. Rice fragments were also found, leading to the belief that the Bronze Age settlers were probably farmers. The site's oldest graves do not include bronze artifacts and are therefore from a Neolithic culture; the most recent graves date to the Iron Age.

The first intensive excavation of Ban Chiang was a joint effort by the University of Pennsylvania Museum and the Thai Department of Fine Arts, with co-directors Chester Gorman and Pisit Charoenwongsa. The aim was not only to investigate the site but to train Thai and western archaeologists in the latest techniques. Because of the looting, they had difficulty finding undisturbed areas to excavate, but settled on two areas 100 meters apart. The locales proved to be far richer in finds than expected, and the distinctive red-on-buff pottery that had excited so much interest proved to be quite late (300 B.C.– AD 200), with many levels of equally noteworthy pottery and other cultural remains beneath them. More exciting, the excavations uncovered crucibles and other evidence of metal working, showing that the villagers of Ban Chiang from an early stage manufactured their own metal artifacts rather than simply importing them from elsewhere. Recovered bronze objects include bracelets, rings, anklets, wires and rods, spearheads, axes and adzes, hooks, blades, and little bells. After the two seasons of excavation, six tons of pottery, stone, and metal artifacts were shipped to the University of Pennsylvania Museum for analysis. The early death of Chet Gorman in 1981, at the age of 43, slowed the process of analysis and publication.

This site has often been called a "cemetery site", but research has suggested that the deceased were buried next to or beneath dwellings. This practice is called residential burial.

At least 142 discrete burials were found in the 1974-1975 excavations. Analysis of the human remains by Michael Pietrusewsky and Michele Toomay Douglas revealed that the people lived a vigorous and active lifestyle with little evidence of interpersonal violence or any form of warfare. The subsistence was based on mixed agricultural/hunting/gathering economy, co-occurring with metallurgy. The conclusion that the centuries-long occupation of the site was largely peaceful is bolstered by the lack of metal weapons.

The excavation at Ban Chiang in 1974–1975 was followed by an article by Chester Gorman and Pisit Charoenwongsa, claiming evidence for the earliest dates in the world for bronze casting and iron working. Subsequent excavations, including that at Ban Non Wat, have now shown that the proposed early dates for Ban Chiang are unlikely. The first datings of the artifacts used the thermoluminescence technique, resulting in a range from 4420–3400 BCE, which would have made the site the earliest Bronze Age culture in the world. These dates stirred world-wide interest. Thermoluminescence dating of pottery was at the time an experimental technique and had been applied to Ban Chiang sherds of uncertain provenance. However, with the 1974–1975 excavation, sufficient material became available for radiocarbon dating. Reanalysis by radiocarbon dating suggested that a more likely date for the earliest metallurgy at Ban Chiang was c. 2000–1700 BCE. A date of 2100 BCE was obtained from rice phytoliths taken from inside a grave vessel of the lowest grave, which had no metal remains. The youngest grave was about 200 CE. Bronze making began circa 2000 BCE, as evidenced by crucibles and bronze fragments. A contrasting analysis was conducted by Charles Higham of the University of Otago using the bones from the people who lived at Ban Chiang and the bones of animals interred with them. The resulting determinations were analyzed using Bayesian statistics and the results suggested that the initial settlement of Ban Chiang took place about 1500 BCE, with the transition to the Bronze Age about 1000 BCE. The chronology of Ban Chiang metallurgy is still in considerable dispute.

Ban Chiang, along with other surrounding villages in northeast Thailand, contains many bronze artifacts that demonstrate that metallurgy had been practiced in small, village settings nearly four thousand years ago. This is of interest to archaeologists, as ancient Southeast Asian metallurgy flourished without the presence of a militaristic or urbanized state, unlike many other ancient societies that had mastered metallurgy.