Background: Children with attention-deficit/hyperactivity disorder (ADHD) frequently struggle with emotional regulation, behavioral issues, and academic performance, leading to peer rejection and social isolation. Objectives: The present study aimed to investigate the effects of acceptance and commitment therapy (ACT) on emotion regulation, behavioral symptoms, and academic performance of children with ADHD. Methods: A quasi-experimental study was conducted using a pretest-posttest design. The study population consisted of all primary school students with ADHD aged 7 - 11, as well as their mothers, in Amol in 2021. A purposive sample of 30 individuals was selected for the study. Participants were assigned to either the ACT training group (n = 15) or the control group (n = 15) through a simple random allocation. The participants in the study filled out questionnaires on emotion regulation, children's behavioral symptoms, and academic performance. The data was analyzed using an analysis of covariance. Results: In the pretest phase, the scores for adaptive emotion regulation strategies, maladaptive emotion regulation strategies, behavioral symptoms, and academic performance were 43.07 ± 6.05, 65.13 ± 9.27, 91.20 ± 12.58, and 128.47 ± 29.84, respectively; whereas in the posttest phase, they were 61.20 ± 8.01, 52.00 ± 6.00, 67.13 ± 12.73, and 159.73 ± 21.11, respectively. Acceptance and commitment therapy resulted in enhanced emotion regulation strategies and academic performance, as well as a decrease in behavioral symptoms in children with ADHD (P < 0.001). Conclusions: Given the effectiveness of acceptance and commitment therapy training in emotion regulation, behavioral symptoms, and academic performance, this approach may be employed by counselors and psychologists at counseling and psychotherapy centers to help remedy ADHD.