This study examined perceived social support from family as a mediator between personality dimensions and psychological well-being among school counselors. To this end, 260 school counselors were selected through random stratified sampling method in Kerman province. The participants were employed by the Ministry of Education in 2013-2014 academic year. The sample took Ryff’s Psychological Well-being Scale, NEO-FFI, as well as the Multidimensional Scale of Perceived Social Support (Zimet et al.). The data were analyzed by structural equation modeling (SEM). Results indicated that the analyzed model had a good fitness index. Moreover, among exogenous variables, personality dimensions and components of perceived social support could significantly predict components of psychological well-being.  More specifically, extraversion, openness to experience, agreeableness, conscientiousness, and perceived social support from family were significant, positive predictors of psychological well-being, whereas neuroticism was a significant, negative predictor of psychological well-being. It can be concluded that school counselors’ psychological well-being is influenced by their personality dimensions as well as their perceived social support. Hence, for the promotion of school counselors’ psychological well-being these components require more attention.