A bailiwick () is usually the area of jurisdiction of a bailiff, and once also applied to territories in which a privately appointed bailiff exercised the sheriff's functions under a royal or imperial writ. The bailiwick is probably modelled on the administrative organization which was attempted for a very small time in Sicily and has its roots in the official state of the Hohenstaufen.

In English, the original French bailie combined with '-wic', the Anglo-Saxon suffix (meaning a village) to produce a term meaning literally 'bailiff's village'—the original geographic scope of a bailiwick. In the 19th century, it was absorbed into American English as a metaphor for a sphere of knowledge or activity.

The term survives in administrative usage in the British Crown Dependencies of the Channel Islands, which are grouped for administrative purposes into two bailiwicks — the Bailiwick of Jersey (comprising the island of Jersey and uninhabited islets such as the Minquiers and Écréhous) and the Bailiwick of Guernsey (comprising the islands of Guernsey, Sark, Alderney, Brecqhou, Herm, Jethou and Lihou). A Bailiff heads each Channel Island bailiwick.

A bailiwick (German: Ballei) was also the territorial division of the Teutonic Order. Here, various “Komtur(en)” formed a Ballei province.