A bailiwick is the area of jurisdiction of a bailiff. The term was also applied to a territory in which the sheriff's functions were exercised by a privately appointed bailiff under a Crown grant. The word is now more generally used in a metaphorical sense, to indicate a sphere of activity, experience, study, or interest.

The term originated in France (bailie being the Old French term for a bailiff) and was used on both sides of the English Channel, although bailiwicks tended to be rather more widespread in northern France than the south. In English, the original French bailie was 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 one's sphere of knowledge or activity.

The term survives in administrative usage in the Channel Islands, which for administrative purposes are grouped into the two bailiwicks of Jersey (comprising the island of Jersey and the islets known as the Minquiers and Ecréhous) and Guernsey (comprising the islands of Guernsey, Sark, Alderney, Brecqhou, Herm, Jethou and Lihou). Each Channel Island bailiwick is headed by a Bailiff.