Focusing on Korean and Korean American usage of hagwons, popular private supplementary educational institutions native to Korea and transmitted to the USA, this article explores the transnational transformation of students’ and parents’ perception and experiences surrounding institutions transmitted from the migrant-sending society to the receiving society. While previous studies of immigrant-led ethnic institutions in the USA focus on these institutions as local institutions developed in the migrant-receiving society and operating in the receiving society contexts, immigrant-led institutions also include transnationally transmitted institutions originating from migrants’ ethnic homelands. Contextualizing immigrant-led ethnic institutions in a transnational framework, this study (1) traces how nonmigrant Koreans perceive and use hagwons in their origin society and (2) examines how (im)migrant Koreans negotiate homeland and hostland norms in navigating the transnationally transmitted institutions. In-depth interviews with nonmigrant and (im)migrant Korean students and parents in Seoul Metropolitan Area, Korea, and Greater Boston, the USA, reveal that immigrants integrate transnational and assimilative strategies in utilizing the transnationally transmitted institutions. Specifically, while deciding to use the tried-and-tested educational institutions transmitted from Korea to educate their second-generation children, immigrant Koreans utilize hagwons in ways that respond to the assimilative needs and constraints of the host society. While hagwons are uniquely Korean and Korean American institutions, their transnational transmission and transformation have implications for better understanding how immigrant experiences—in this case, education of immigrants and their children—are shaped at the intersection of the sending society and the receiving society influences.