In an effort to decrease the suicide rate in adolescents, many interventions have focused on school-based suicide prevention programs. Alternatively, depression education in schools might be effective in decreasing the morbidity, mortality, and stigma associated with adolescent depression. The Adolescent Depression Awareness Program (ADAP) developed a 3-hour curriculum to teach high school students about the illness of depression. The purpose of this study was to assess the effectiveness of the ADAP curriculum in improving high school students' knowledge about depression. From 2001 to 2005, 3,538 students were surveyed on their knowledge about depression before and after exposure to the ADAP curriculum. The number of students scoring 80% or higher on the assessment tool more than tripled from pretest to posttest (701 to 2,180), suggesting the effectiveness of the ADAP curriculum. Further study and replication are required to determine if improved knowledge translates into increased treatment-seeking behavior. (Contains 4 tables.)