Objective:In this study, we planned to investigate the effectiveness of life skills training on the social skills of students with intellectual disabilities. Methods:In this experimental study, with pretest and posttest design and control group, an equal number of participants was randomly assigned to experimental and control group. Life skills training were provided to experimental group (n=20) in nine sessions, whereas control group was in neutral state. The teacher completed the pretest and posttest Social Skills Rating Scale (Teacher Form) for the participants. The data were analyzed by multivariate analysis of covariance (MANCOVA) using SPSS software. Results:The results of MANCOVA revealed a significant difference between total social skills and subscales of the test (cooperation, assertiveness, and self-control) in the experimental group (P<0.005), whereas there was no significant difference in the control group. It is important that educators and parents reinforce learning of social skills through direct and indirect life skills training procedure. Conclusion:The results of this study support the effectiveness of life skills training including cooperation, assertion, and self-control on social skills of high school students with intellectual disabilities.