The Southward expansion of the Han dynasty was a series of Chinese military campaigns and expeditions in what is now modern Southern China and Northern Vietnam. Military expansion to the south began under the previous Qin dynasty and continued during the Han era. Campaigns were dispatched to conquer the Yue tribes, leading to the annexation of Minyue by the Han in 135 BCE and 111 BCE, Nanyue in 111 BCE, and Dian in 109 BCE.

Han Chinese culture took root into the newly conquered territories and the Baiyue and Dian tribes were eventually assimilated or displaced by the Han Empire. Evidence of Han dynasty influences are apparent in artifacts excavated in the Baiyue tombs of modern southern China. This sphere of influence eventually extended to various ancient Southeast Asian kingdoms, where contact led to the spread of Han Chinese culture, trade and political diplomacy. The increased demand for Chinese silk also led to the establishment of the Silk Road connecting Europe, the Near East, and China.