This study is an investigation of the epistemological beliefs of South Korean middle school students and their relation to self-directedness in learning. A total of 700 students from seven middle schools participated in the survey. The result revealed the four dimensions of epistemological beliefs (i.e., Learning Effort/Process, Authority/Expert Knowledge, Innate/Fixed Ability, and Certainty of Knowledge). All of the epistemological dimensions are significantly related to self-directedness in learning. Korean middle school students in general tended to value "Learning Effort/Process" but did not rely on "Authority/Expert Knowledge." In contrast to the previous research results, self-directed learners were more likely to believe in certainty of knowledge. The results of this current study also included epistemological differences by grade, gender, and top and bottom SDL scores. Implications of this study for teaching practice to improve students' SDL are discussed.