Different cultural assumptions of “selfhood” in East and West cultures provide the individuated self-concept in West and collective self-concept in East, which in turn influence how individuals judge their well-being and mental health. While discussing how culture influences formation of self-concept, this paper examines the relationship between cultural pattern of collectivism and self-esteem with well-being among Iranian and Canadian female students. The results show that in Iranian girls collective tendencies have a significant role in formation of self-concept and in mental health, whereas for Canadian girls personal self-esteem is the most important factor.