Dian was an ancient kingdom established by the Dian people, a non-Han metalworking civilization that inhabited around the Dian Lake plateau of central northern Yunnan, China from the late Spring and Autumn period until the Eastern Han dynasty. The Dian buried their dead in vertical pit graves. The Dian language was likely one of the Tibeto-Burman languages. The Han Empire's annexation of the Dian Kingdom in 109 BCE eventually led to the establishment of the Yizhou commandery. Dian culture started from at least the 8th century BCE, until it fell under the control of the Han dynasty in 109 BCE.

Dianchi Lake, also known as Lake Dian and Kunming Lake, is a large lake located on the Yunnan-Guizhou Plateau close to Kunming, Yunnan, China. Its nickname is the "Sparkling Pearl Embedded in a Highland" and it was the model for the Kunming Lake in the Summer Palace in Beijing. Its name is the source of Yunnan's Chinese abbreviation 滇.