Bisaltia (Bisaltica) was an ancient region extending from the river Strymon and Lake Cercinitis on the east to Crestonia on the west. The eponymous inhabitants, known as the Bisaltae, were a Thracian people. The most important town in Bisaltia was the Greek city of Argilus . There was a river named Bisaltes in the region, which has not been certainly identified.

Bisaltia, along with Crestonia, was ruled by a Thracian prince at the time of Xerxes' invasion, but by the onset of the Peloponnesian War it was annexed to Macedon.

Most of Bisaltia is now within the eastern portion of the Thessaloniki prefecture in Greece.