Lifelong education indicates education and learning involved in one’s entire life, emphasizing learning all through life from the cradle to the grave, and covers home education, social education, school education, vocational education, and post-retirement education. As language and thinking are also core abilities in lifelong education, the role and the responsibility of Korean language education have been greater. Therefore, Korean language education needs to establish the idea of ‘lifelong Korean language education’ which helps language education for lifelong developmental stages beyond Korean language education as a tool subject of school curricula. Lifelong Korean language education studies are interdisciplinary as lifelong education has a feature of comprehensive and integrative studies. In the dimension of lifelong education, Korean language education is required to play a more fundamental role as a subject to promote literacy. Considering illiteracy phenomenon which appears as about ten percent among the national population in developed countries globally, the number of illiterate students among teenagers are increasing in Korea. For safeguard for human rights and economic improvement, Korean language education for eradicating adult illiteracy and illiterates at schools should be exhaustively implemented from elementary school.