: The purpose of this study is to identify the gender differences in identity styles, commitment and quality of friendship. For this reason, 400 high school students from 19 educational regions in Tehran (males –females) are chosen randomly. Three scales are administrated: identity style inventory-six grade (White et al, 1998), quality of friendship (Hejazi, Zohrevand, 1380) and Socio-metric questioner. The results show that:
-females use informational identity style more than males;
-there is no significant gender difference in normative, diffuse/avoidant, and commitment identity styles;
-females are higher than males in intimacy, self-disclosure, and reciprocity friendship;
-there is not a gender difference in proximity, trust, and royalty.