The purpose of this study is to shed light on the efficacy of various suicide preventive interventions for adolescents using meta-analysis. Specifically, this study aims to examine the effects of primary (1st prevention), secondary (2nd prevention), and tertiary (3rd prevention) suicide preventive interventions on direct suicidal and suicide-related outcomes (risk factors and protectors for suicide) and further identify which types of intervention show a high effect under the context of the 1st, 2nd, and 3rd preventions. Suicidal ideation and impulse were included in the suicidal index, depression and negative automatic thoughts in the risk factor index, and self-esteem, problem-solving skills, and life-respecting attitude in the protector index. Thirty-seven suicide studies (one outlier study was excluded) published between 1991 and 2020 were meta-analyzed. Comprehensive Meta-Analysis (CMA) 3.0 software was used for the meta-analysis. The results are as follows. The average effect size of suicide preventive interventions for adolescents is 0.74. Average effect sizes of the 1st, 2nd, and 3rd preventions were 0.44, 1.07, and 1.24, respectively, revealing better effects in the 2nd and the 3rd preventions than in the 1st prevention. The similarly better effects of the 2nd and the 3rd preventions than the 1st prevention were found for the indices of suicide, risk factor, and protector. Under the context of the 1st prevention, the program promoting respect for life and smile treatment showed relatively better effects as compared to Cognitive Behavior Therapy (CBT) and the preventive education group. Under the context of the 2nd prevention, CBT, mindfulness+ACT, reality therapy, narrative therapy, and art therapy showed large effects on suicide and the suicide-related indices. Under the context of the 3rd prevention, only CBT was applied and showed large effects on suicide and the suicide-related indices. Clinical implications of these findings were discussed.