The aim of this study was to examine the effectiveness of music therapy on the executive functions of aggressive female students. This quasi-experimental research had a pretest-posttest control group design. Random cluster sampling method was utilized and 30 aggressive students were selected from among female elementary school students in District 4 of Karaj in 2020-2021 school year. The drawn sample was randomly assigned to the experimental and control groups. The research instruments included the Aggression of Elementary School Children Questionnaire (Shahim, 2006), The Wisconsin Card Sorting Test (Grant & Berg, 1948), the Continuous Performance Test (Rosvold et al., 1956), and the Stroop test (1935). The experimental group underwent music therapy in 8 sessions. Data were analyzed via multivariate analysis of covariance. Results showed that in the experimental group, cognitive flexibility increased significantly compared to the control group (p<0.001). On the continuous performance test, a significant effect was observed on improved sustained attention in the experimental group (p<0.001) because the number of errors in the experimental group decreased compared to the control group. On the Stroop test, a significant effect was observed on improving inhibition in the experimental group (p<0.001). Thus, it can be concluded that music therapy significantly improves the aggressive female students’ executive functions (cognitive flexibility, sustained attention, and inhibition). Therefore, it is suggested that music therapists utilize this treatment to help aggressive students in educational and therapeutic settings. The findings of this research can have many educational implications.