The Regency of Algiers was a largely independent tributary state of the Ottoman Empire during the early modern period, located on the Barbary Coast of North Africa from 1516 to 1830. Founded by the corsair brothers Aruj and Hayreddin Barbarossa, the Regency was a formidable pirate base infamous for its corsairs. First ruled by Ottoman regents, it later became a sovereign military republic that plundered and waged maritime holy war against European Christian powers.

The Barbary Coast was the name given to the coastal regions of central and western North Africa or more specifically the Maghreb and the Ottoman borderlands consisting of the regencies in Algiers, Tunis, and Tripoli, as well as the Sultanate of Morocco from the 16th to 19th centuries. The term originates from the exonym of the Berbers.