Background: Medical professionalism includes cognitive, skills, and professional behavior abilities. Unprofessional behaviors by doctors are associated with adverse events, medical errors, and patient dissatisfaction. Student`s behavior during their study can determine their future hence learning professional behavior needs to be introduced early. Assessment of professional behavior can be used as early evaluation for students in order to support professional behavior`s learning. The assessment may include self-assesment and supervisor assessment. Objective: To find out the relationship between self-assesment and supervisor assessment on “Ilmu Kesehatan Gigi Masyarakat (IKGM)” module activities toward students professional behavior in School of Dentistry Universitas Muhammadiyah Yogyakarta 2019. Method: The type of research was analytical observational with cross-sectional design. It was held on January - Maret 2019 at Dental Hospital of UMY with the total 89 students and 10 instructors who were eligible the inclusion criteria and were selected by using total sampling method. Professional behavior was measured by Penn State College of Medicine (PSCOM) Questionnaire consists of 30 item statements that was distributed to students and supervisor during the IKGM module activities. The data were analyzed by Pearson correlation test. Result: The result show that value of correlation is -0.157 and p value is 0.141, which is p>0.05. Conclusion: The research shows that there was no significant relationship between self-assesment and supervisor assessment on IKGM module activities toward student professional behavior in School of Dentistry Universitas Muhammadiyah Yogyakarta 2019.