Yuzhno-Kurilsk is an urban locality and the administrative center of Yuzhno-Kurilsky District of Sakhalin Oblast, Russia. Population: 5,832 (2010 Russian census); 5,751 (2002 Census); 6,344 (1989 Soviet census). It is the largest settlement on the Kunashir Island of the Kuril Islands.

Kunashir Island, possibly meaning Black Island or Grass Island in Ainu, is the southernmost island of the Kuril Islands archipelago. The island has been under Russian administration since the end of World War II, when Soviet forces took possession of the Kurils. It is claimed by Japan.