Korean (한국어/조선말, see below) is the official language of both Koreas: the Republic of Korea and the Democratic People's Republic of Korea, with different official forms used in each nation-state. It is also one of the two official languages in the Yanbian Korean Autonomous Prefecture and Changbai Korean Autonomous County of the People's Republic of China. Approximately 80 million people worldwide speak Korean.

Korean has a few extinct relatives, which together with Korean itself form the Koreanic language family. Despite this, historical and modern linguists classify Korean as a language isolate; however, the classification of the Jeju language as a distinct language necessarily implies that Korean is not an isolate, but a member of a small family. The idea that Korean belongs to the controversial Altaic language family or to the Dravido-Korean family has been largely discredited, particularly with the modern academic consensus debunking the Altaic language group entirely. There is still debate on whether Korean and Japanese are related languages. The Korean language is agglutinative in its morphology and SOV in its syntax.