Koreans in Japan comprise ethnic Koreans who have permanent residency status in Japan or who have become Japanese citizens, and whose immigration to Japan originated before 1945, or who are descendants of those immigrants. They are a group distinct from South Korean nationals who have immigrated to Japan after the end of World War II and the division of Korea.

Koreans are an East Asian ethnic group native to Korea. The majority of Koreans live in the two Korean nation states of North and South Korea, which are collectively referred to as Korea. As of 2021, an estimated 7.3 million ethnic Koreans resided outside of Korea. Koreans are also an officially recognised ethnic minority in other several Continental and East Asian countries, including China, Japan, Kazakhstan, Russia, and Uzbekistan. Outside of Continental and East Asia, sizeable Korean communities have formed in Germany, the United Kingdom, France, the United States, Canada, Australia, and New Zealand.