The Kuril Islands dispute, known as the Northern Territories dispute in Japan, is a territorial dispute between Japan and Russia over the ownership of the four southernmost Kuril Islands. The Kuril Islands are a chain of islands that stretch between the Japanese island of Hokkaido at their southern end and the Russian Kamchatka Peninsula at their northern end. The islands separate the Sea of Okhotsk from the Pacific Ocean. The four disputed islands, like other islands in the Kuril chain which are not in dispute, were unilaterally annexed by the Soviet Union following the Kuril Islands landing operation at the end of World War II. The disputed islands are under Russian administration as the South Kuril District and part of the Kuril District of the Sakhalin Oblast. They are claimed by Japan, which refers to them as its Northern Territories or Southern Chishima, and considers them part of the Nemuro Subprefecture of Hokkaido Prefecture.

The Kuril Islands or Kurile Islands are a volcanic archipelago administered as part of Sakhalin Oblast in the Russian Far East. The islands stretch approximately 1,300 km (810 mi) northeast from Hokkaido in Japan to Kamchatka Peninsula in Russia, separating the Sea of Okhotsk from the north Pacific Ocean. There are 56 islands and many minor islets. The Kuril Islands consist of the Greater Kuril Chain and, at the southwest end, the parallel Lesser Kuril Chain. They cover an area of around 10,503.2 square kilometres (4,055.3 sq mi), with a population of roughly 20,000.