Aim: This study aimed to investigate the effects of a psychoeducation program on emotional expression and mood regulation among mothers of children diagnosed with Autism Spectrum Disorder (ASD). Method: The research employed a quasi-experimental design with pre-test and post-test control groups. The study sample consisted of 28 mothers whose children were attending the Selçuklu Foundation for the Education of Individuals with Autism (SOBE) in Konya, Turkey. The experimental group participated in a 10-week psychoeducation program, while no intervention was provided to the control group. Data were collected using the Emotional Expression Scale, the Negative Mood Regulation Scale (NMRS), and a Personal Information Form developed by the researcher. The data were analyzed using mixed-design two-way ANOVA and paired and independent samples t-tests. Results: The findings indicated that the psychoeducation program led to significant improvements in emotional expression and mood regulation among mothers in the experimental group. Moreover, these positive effects persisted for up to eight weeks following the completion of the program, suggesting its long-term impact. Conclusion: The results demonstrate that structured psychoeducational interventions can effectively enhance emotional coping skills in mothers of children with ASD and contribute to their emotional well-being over time.