Background and purpose: intellectual disability can lead to behavioral problems such as aggression. Various studies have shown that social skills training have positive effects on children’s behaviors.  The purpose of the current study was to investigate the effects of social skills training on the reduction of verbal and nonverbal aggression in male students with intellectual disability.

Method: current research was an experimental study with pretest- posttest control group design. The population consisted of all male students with intellectual disability in 2010-2011 academic year in Lordegan. Sample consisted of 30 male students that were selected using random cluster sampling method. Data were collected using the Inventory of Aggression for Children with Intellectual Disability (QezelSeflo, Bahrami, Davarmanesh, 2007). The students in experimental group participated in an eleven-session social skills training program (consisted of two one-hour sessions per week), while control group received no training program. Both groups participated in pretest and posttest. Univariate analysis of covariance was used for data analysis.

Results: Results showed that participating in social skills training program could significantly decrease aggression in the areas of total aggression (p < .05), self-verbal and nonverbal aggression (p < .05), and verbal and nonverbal aggression towards others (p < .05) in male students with intellectual disability.

Conclusion: According to our findings, by learning social skills, students with intellectual disability show less aggressive strategies in facing different situations.