Objectives:The study aims to investigate the effectiveness of Cognitive-Behavioral Play Therapy (CBPT) on the self-esteem of children with intellectual disability. Methods:Pre-test and post-test, control group, quasi-intervention design was adopted for the study. The study sample consisted of 40 children conveniently selected based on the inclusion and exclusion criteria from among educable intellectually-disabled children in two care centers for children with special needs in Tehran, who were randomly assigned into intervention and control groups. In both the groups, the pre-test was conducted by the Cooper-smith SelfEsteem Inventory (CSEI) and then for the intervention group, CBPT sessions were performed in 12 sessions of 60-minute each (two days a week). The post-test was also administered to both the groups after intervention. The data obtained were analyzed using independent t-test and Levine's test by SPSS software.Results: Self esteem was observed to be significantly increased in the intervention group (P<0.01) as compared with the control group. Discussion: It seems that play therapy is an effective method to increase self esteem in children with intellectual disability. Therefore, educators and teachers are advised to use this method as an adjunctive therapy for such children in rehabilitation centers and schools.