Purpose: The purpose of this study was to investigate the level of mental health literacy (MHL) among parents of adolescents and middle and high school teachers in Korea. Methods: A descriptive cross-sectional survey design was used for the present study. Participants were 120 parents and 103 middle and high school teachers in Korea. In 2014-2015 participants completed a survey about two case vignettes(adolescent schizophrenia and depression) and answered questions assessing recognition of these disorders and belief about the helpfulness of interventions and resources. Descriptive analysis, t-test and x2 test were performed. Results: Schizophrenia was recognized by only 11.6% of parents and 25.2% of teachers. Depression was recognized by 32.5% of parents and 59.2% of teachers. Both parents and teachers acknowledged individual and socio-environmental factors as causes for schizophrenia and depression. However, they were less likely to recognize biological factors as potential causes for mental illness. Conclusion: The findings demonstrate the need for education programs for parents of adolescents and teachers to improve their mental health literacy, particularly concerning biological causes of mental illness.