The present study aimed to compare the efficacy of cognitive-behavioral play therapy and narrative therapy on aggression and assertiveness of students with an educable intellectual disability. This study followed a quasi-experimental research design with a pre-test, post-test, and a control group. The statistical population included all students with an educable intellectual disability enrolled in Tabriz elementary schools, of whom 45 male students were randomly assigned to two experimental and one control groups (15 per group) using convenience sampling. The Shahim Aggression Questionnaire for Elementary School Students (2006) and the Gmbryl and Ritchie’s Assertiveness Questionnaire (1975) were used to collect data. After the pre-test, one of the experimental groups received a play therapy program while the other group received narrative therapy. Afterward, all the groups sat for a post-test. Moreover, although the control group did not receive any therapy, they were required to participate in pre-and post-tests and complete the questionnaires. The covariance analysis revealed a significant difference in aggression and assertiveness between cognitive-behavioral play therapy, narrative therapy and the control groups (0.001). Narrative therapy was more effective at reducing aggression than cognitive-behavioral play therapy, with an effect size of 69%. Additionally, narrative therapy was more effective than play therapy at increasing assertiveness, with an effect size of 74%. Thus, narrative therapy and cognitive-behavioral play therapy can be used in conjunction to alleviate psychological problems in students with educable intellectual disabilities.
