The purpose of this paper is to analyze the direction and activities of Korean teachers’ unions, such as the Korean Teachers and Education Workers Union (KTU) and the Korean Federation of Teachers Unions(KFTU), from an educational-philosophical perspective through the “Teacher Theory of Paulo Freire.” The “Teacher Theory of Paulo Freire” calls for teachers and teachers’ unions to have “humble confidence” Humility of conviction means having a direction and striving to implement it, while at the same time being intellectually flexible and actively accepting the opinions of others and social changes. From Paulo Freire’s perspective, it is justifiable for KTU to have a political orientation. However, it should always reflect on its own direction and express it to students in a horizontal and open manner. Moreover, KFTU should not limit themselves to an interest group, but establish clear educational beliefs and social values, and strive to implement them. In other words, KTU needs to embody “humility” and KFTU needs to have “conviction” in the “humble confidence” of “Teacher Theory of Paulo Freire.”