American-born Korean-Americans show one of the highest rates of heritage language attrition among immigrant groups in the United States. This literature review aims to identify factors that influence Korean heritage learners' motivation to maintain or disengage from heritage language learning, particularly focusing on language learning settings, learning opportunities, and learners' experiences and perceptions about the language and learning. First, it reviews research that informs about the current status of Korean mainly as a heritage language in American K-16 schools where learner motivation and language learning are positioned. The second section explores the circumstances of Korean language use and exposure taking place in the Korean community setting. The third section explores the ways in which heritage language maintenance is influenced by Korean heritage learners' diverse experiences in association with the perceived language vitality, ethnic and linguistic identity formation, and individual differences in learning goals and backgrounds. On the basis of the literature review, the last section discusses the argument that the systemic relations of the K-16 education community, the Korean community, and individual learners are critical in understanding Korean heritage learners' involvement in language learning and development. Finally, this Report concludes with recommendations for the enhancement of learning opportunities and motivation for Korean learners and with suggestions for future research in the nascent field of Korean education and research in the United States. / text