Abstract Background The study investigated the long-term effectiveness of the adolescent cognitive behavioral resiliency training Op Volle Kracht (OVK) on the secondary outcomes: anxiety symptoms, hopelessness, happiness, life satisfaction, optimism, coping, self-efficacy, and school functioning. In addition, the study analyzed whether the secondary outcomes moderated the intervention effect on depressive symptoms. Methods A two-condition (intervention and control) cluster randomized controlled trial was conducted. All adolescents in the 8 th grade were eligible to participate, unless they, or their parents, declined their participation. Schools were the unit of randomization. Missing data were imputed and intent to treat analyses were conducted. The results were analyzed using Latent Growth Curve Modeling across the 24-months follow-up period. Results The total sample consisted of 1341 adolescents ( M age = 13.91, SD =0.55, 47.3% girls, 83.1% Dutch ethnicity). The intervention and control condition consisted of 634 adolescents from 4 schools and 707 adolescents from 5 schools, respectively. OVK did not have an effect on depression, anxiety, hopelessness, happiness, and life satisfaction, but promoted cognitive coping over the course of the follow-up period. OVK showed small iatrogenic effects on optimism, active coping, social self-efficacy and school grades directly post intervention, but these effects disappeared during the follow-up period. Finally, none of the outcome variables moderated the intervention effect on depressive symptoms. Conclusions The universal resiliency training OVK was not effective in this Dutch sample. Implications for research and practice were discussed. Trial registration number NTR2879