The purpose of this study was to evaluate the effectiveness of suicide prevention group programs for Korean adults by using a meta-analysis. For this purpose, adults over the age of 19 years were selected as major research subjects and the effect sizes according to the approach and type of programs were analyzed by the age subgroups. Adults were classified into their representative groups according to the life cycle: Middle aged, soldiers, college students, and the elderly group. The overall effect of the programs and their effects on dependent variables were calculated for suicide ideation and depression as the main indicators of suicide prevention programs. The moderating effects were analyzed with moderator variables, including sex, degree of suicide risk, clinical group diagnosed with psychiatric disorders, program approach, program type, number of sessions, period of the operation, minutes per session, times per week, and number of group members. A total of 26 studies published in Korea from 2000 to 2020 were selected, and 60 effect sizes were calculated using the random-effects model. The results were as follows: First, the overall effect size was 0.858, indicating a large effect size, and the effect size of suicide ideation was medium (g=0.741), and the effect size of depression was large (g=0.987). Secondly, based on the effect sizes according to the other moderator variables, the programs developed for the same sex group, high risk suicidal group, and the clinical group diagnosed with psychiatric disorders were the most effective. With respect to the parameters of the group operation, 11∼20 sessions and a duration of 5∼8 weeks were the most effective. Thirdly, according to the participant type, the effect size was in the following order: middle aged, soldiers, college students, and the elderly group. The effect sizes for the middle aged and soldiers were large, whereas the effect sizes for college students and the elderly were medium; the difference between these groups was statistically significant. In the analysis by subgroups, the effect sizes of a network approach, interpersonal psychotherapy, and integrative therapy were large in the elderly group. Also, cognitive behavioral therapy was most effective in the middle aged, soldiers, and college student groups. The effect size of art therapy was also large in the soldiers group. Based on these findings, implications and suggestions for future research were discussed.