The Han–Xiongnu War, also known as the Sino-Xiongnu War, is a series of military conflicts fought between the Chinese Han empire and the nomadic confederation of Xiongnu tribes between 133 BCE and 89 CE.

Under the reign of Emperor Wu, the Han empire changes from a relatively passive foreign policy to an offensive strategy in order to deal with the increasing Xiongnu incursions on the northern frontier.

After a failed attempt to ambush the raiding Xiongnu army at Mayi in 133 BCE, the Han court decides to deploy several military expeditions towards the regions at the Ordos Loop, Hexi Corridor, and Gobi Desert in a successful attempt to conquer it and expel the Xiongnu, and the conflict escalates to a full-scale war.

Hereafter, the war progresses further towards the many smaller states of the Western Regions.

The nature of the battles varies through time, with many casualties during the changes of possession and loss of the western frontier regions.

During this conflict, the Han empire's political influence expands deeply into Central Asia.

As the situation deteriorates for the Xiongnu, civil war befalls the confederation.

Marked by significant events involving the conquests over various smaller states for control and many large-scale battles, the war results in the total victory of the Han empire over the Xiongnu state in 89 CE.