Purpose: The purpose of this study was to evaluate the effects of a core competency support program on depression and suicidal ideation in adolescents. Methods: A quasi-experimental design was employed in this study. Participants for the study were high school students, 27 in the experimental group and 29 in the control group. Data were analyzed using the SPSS/WIN. 14.0 program with $chi^2$ test, t-test, and ANCOVA. Results: Participants in the core competency support program reported decreased depression scores significantly different from those in the control group. Participants in the core competency support program reported decreased suicidal ideation scores, also significantly different from those in the control group. Conclusion: The core competency support program was effective in decreasing depression and suicidal ideation for adolescents. Therefore, this approach is recommended as a suicide prevention strategy for adolescents.