The Jemdet Nasr Period is an archaeological culture in southern Mesopotamia. It is generally dated from 3100 to 2900 BC. It is named after the type site Tell Jemdet Nasr, where the assemblage typical for this period was first recognized. Its geographical distribution is limited to south-central Iraq. The culture of the proto-historical Jemdet Nasr period is a local development out of the preceding Uruk period and continues into the Early Dynastic I period.

Jemdet Nasr is a tell or settlement mound in Babil Governorate (Iraq) that is best known as the eponymous type site for the Jemdet Nasr period, and was one of the oldest Sumerian cities. It is adjacent to the much larger site of Tell Barguthiat. The site was first excavated in 1926 by Stephen Langdon, who found Proto-Cuneiform clay tablets in a large mudbrick building thought to be the ancient administrative centre of the site. A second season took place in 1928, but this season was very poorly recorded. Subsequent excavations in the 1980s under British archaeologist Roger Matthews were, among other things, undertaken to relocate the building excavated by Langdon. These excavations have shown that the site was also occupied during the Ubaid, Uruk and Early Dynastic I periods. Based on texts found there mentioning an ensi of NI.RU that is thought to be its ancient name. During ancient times the city was on a canal linking it to other major Sumerian centers.