Background and Aim: Childhood is a critical period for mental health and behavioral development. This study examined the effectiveness of the 1-2-3 discipline program on parenting skills, discipline, independence, and responsibility in children aged 8 to 12 years.

Methods: This quasi-experimental study used a pretest–posttest–follow-up design with a control group. The statistical population included parents of children aged 8 to 12 years in Isfahan in winter 2025 who had referred to counseling centers active in child and adolescent services. A total of 40 parents were selected through convenience sampling and randomly assigned to experimental and control groups (20 in each group). Data were collected using the Parenting Skills Questionnaire (Fine et al.), the Self-Regulation/Discipline Questionnaire (Davis), the Emotional Independence Questionnaire (Sternberg and Silverberg), and the Responsibility Questionnaire (Lewis). The experimental group received the 1-2-3 discipline program developed by Phelan and Lewis in 10 sessions of 90 minutes, while the control group received no intervention. Data were analyzed using repeated-measures analysis of variance in SPSS version 26.

Results: repeated-measures ANOVA showed significant effects of the intervention on parenting skills (F = 13.54, p < 0.001, η² = 0.263), discipline (F = 18.96, p < 0.001, η² = 0.333), independence (F = 14.12, p < 0.001, η² = 0.271), and responsibility (F = 34.85, p < 0.001, η² = 0.478).

Conclusion: The 1-2-3 discipline program effectively improved parenting skills, discipline, independence, and responsibility in children aged 8 to 12 years.