Purpose: The purpose of this study was to investigate the teachers` attitudes, discrimination, and causes of prejudice towards people with mental illnesses. Methods: A cross-sectional study design was used and participants included 158 teachers who were recruited from four schools in S and G cities, Korea. From October to December, 2011, data on general characteristics, attitudes, discrimination and causes of prejudice towards people with mental illnesses were collected using self-administered questionnaires. SPSS/WIN 18.0 version was used for descriptive analysis, t-test, one-way ANOVA, and Pearson correlation. Results: The mean scores of teachers` attitudes towards people with mental illness were, authoritarianism, 3.24, benevolence, 2.96, social restrictiveness, 3.44 and community mental health ideology, 2.75. There were significant differences in benevolence according to age. The experience of meeting people with mental illness contributed to positive attitudes towards people with mental illness in the benevolence subscale. There were significant differences in social restrictiveness according to residence. There were significant differences in discrimination according to age. Subscales of attitudes were significantly correlated with discrimination. Conclusion: These results emphasize a need for continuous education not only of teachers but also of the general population.