The aim of the present study was to investigate the effect of group logotherapy with a religion-based approach on students’ aggression and hopelessness. This quasi-experimental research had a pretest posttest control group design. The population of the study was comprised of all eleventh grade girls in Robatkarim in academic year 2014-2015. The sample included 240 students who were selected through multi-stage cluster sampling method. The instruments included Beck’s Hopelessness Scale (1988)‌ and Ahvaz Aggression Inventory (Zahedifar et al., 2000). Thirty students who had obtained the highest scores on the two scales were selected and randomly assigned to experimental (N=15) and control groups (N=15). The experimental group received the intervention (group logotherapy with a religion-based approach) in ten 75-minute sessions. Both groups were given the posttest after two weeks. The obtained data were analyzed via ANCOVA. The results showed that there was a significance difference between the mean scores of the two groups in hopelessness (p≤0.001, F=4.89) and aggression (P≤0.001, F=58.69) in the pretest and posttest (P≤0.001). The findings indicated that group logotherapy with a religion-based approach can decrease hopelessness and aggression and boost mental health among students.