This article presents a discussion of the development of Jeongyojo or the Korean Teachers and Educational Workers Union from its emergence as a social movement in the late 1980s to its current status and prominent campaigns. The article identifies certain aspects of South Korean history and culture that have shaped the distinctive identity of this teachers union. The article recognizes that, despite legalization some years ago, the Korean Teachers Union continues to engage in controversial campaigns that frequently cause conflicts with the Ministry of Education in South Korea. The article points towards the set of principles of True Education (Chamgyoyook) that provide the guiding framework for the union's activities at home and internationally.