Qasr al-Hallabat is an Umayyad desert castle, with the associated bath house of Hammam as-Sarah east of it. The nearby modern town, named after the castle, is part of the Zarqa Governorate of north-western Jordan, north-east of the capital of Amman.

The complex of Qasr al-Hallabat is located in Jordan's eastern desert. Originally a Roman structure constructed in the 2nd-3rd century AD to protect the eastern frontiers of the Roman Empire, although there is trace evidence of Nabatean presence at the site. It was one fort of many on the Roman highway, Via Nova Traiana, a route that connected Damascus to Aila (modern-day Aqaba) by way of Petra and Philadelphia (modern-day Amman).

In the 6th century, the fort was ceded to the Ghassanids as part of the foedus treaty with the Byzantine emperor Justinian. The Ghassanids significantly altered the structure and constructed a monastery. By the 8th century, the Umayyad caliph Hisham ibn Abd al-Malik ordered the structures to be demolished in order to redevelop this military site and its neighboring territory to become one of the grandest of all Umayyad desert complexes.