The aim of the present study was to investigate the effect of a selected physical activity program on self-esteem, mental health, and physical competence of children with autism spectrum disorder. This quasi-experimental study was conducted using a pretest-posttest design with a control group. The statistical population included autistic children aged 8 to 12 years, 32 of whom were selected conveniently and randomly assigned to two experimental and control groups (16 people each). The experimental group participated in the selected physical activity program for three 45-minute sessions per week for 8 weeks, and the control group performed its usual program. The instruments included the Rosenberg Self-Esteem Scale, the Children's Mental Health Questionnaire, and the Harter Physical Competence Scale. The data were analyzed using multivariate and univariate analysis of covariance. The results showed that the overall effect of the intervention on the set of variables was significant (p<0.001, F=18.42). Also, the results showed that there was a significant difference between the two groups in self-esteem (p<0.001, F=28.14), mental health (p<0.001, F=22.87), and physical competence (p<0.001, F=25.63), and the experimental group obtained higher scores. These findings indicate that selected physical activity can be an effective, low-cost, and non-invasive intervention to improve the psychological and cognitive dimensions of children with autism.