The Pitcairn Islands (; Pitkern: Pitkern Ailen), officially the Pitcairn, Henderson, Ducie and Oeno Islands, are a group of four volcanic islands in the southern Pacific Ocean that form the sole British Overseas Territory in the Pacific Ocean. The four islands—Pitcairn, Henderson, Ducie, and Oeno—are scattered across several hundred miles of ocean and have a combined land area of about 18 square miles (47 km2). Henderson Island accounts for 86% of the land area, but only Pitcairn Island is inhabited. The islands nearest to the Pitcairn Islands are Mangareva (of French Polynesia) to the west and Easter Island to the east.

Pitcairn is the least populous national jurisdiction in the world. The Pitcairn Islanders are a biracial ethnic group descended mostly from nine Bounty mutineers and a handful of Tahitian consorts – as is still apparent from the surnames of many of the islanders. This famous mutiny and its aftermath have been the subject of many books and films. As of January 2020, the territory had only 47 permanent inhabitants.