This study was to examine the factors that affect the oral health knowledge of elementary school students. This study surveyed a comparative study of the students and guardians' oral health knowledge among the elementary schools operating or not operating school dental clinic program in Jeollanamdo. The subjects were 178 elementary school students and guardian, structured questionnaires were performed during the period from May 2 to May 26, 2014. As a result, non-operated school dental clinic program had a negative effect on Oral health knowledge of students, but it was not significant. The factors associated with student's oral health knowledge turned out to be oral heath education experience of guardian, oral health education participation of student, self-reported oral health of student. In conclusion, student's oral health knowledge was influenced by student's and guardian's oral health-related behaviors, oral health status of student.