Open AccessThis study made an attempt to investigate the relationship between the social intelligence andaggression among the high school boy students in Kashan city, Iran. To conduct this study,descriptive-correlational research method was used. Descriptive method was used to describethe current status of the student’s social intelligence and aggression .Correlational methodwas used to investigate the relationship between the social intelligence and aggression.Population of the study incorporated 3850 high school boy students of kashan city in theacademic year 2010-2011.Of this population, 423 subjects were chosen through multistagecluster sampling method. To assess the subjects, measurement tools such as Buss Perry(1992)aggression questionnaire and Thout(1995) social intelligence questionnaire were used. Whenit came to the analysis of the obtained data, correlation coefficient and regression coefficientwere used. The results showed that there was a significant relationship between the socialintelligence and aggression ,especially verbal aggression , physical aggression ,violence ,andhostility among the high school boy students in Kashan city .The results also showed that themore students’ social intelligence is, the less their aggressive behavior become .Therefore, todecrease the students’ aggressive behaviors, their social intelligence should be improvedthrough appropriate curriculum planning ,and through holding in-service education programsand educational workshops for the principals.