According to general aggression model, it is expected that antisocial and prosocial tendencies can be affected by family-related variables. The present study sought to predict aggression and moral identity based on family cohesion, family communication patterns and family social support. The research design was correlational and the population of the study was comprised of male high school students in Estahban in 2018-19 school year. The sample consisted of 253 individuals who were selected through cluster sampling method. The research instruments included Aggression Questionnaire (Buss & Perry, 1992), Self-Importance of Moral Identity Scale (Aquino & Reed, 2002), Social Support Questionnaire (Vaux et al., 1986), Revised Family Communication Patterns Scale (Koerner et al., 2002), Family Cohesion Questionnaire (Samani, 2002) and Crowne & Marlowe Social Desirability Scale (1982). Data were analyzed via Pearson correlation, partial correlation and multiple regression by SPSS22. Results revealed that conversation orientation as a communication pattern and family cohesion correlated to aggression negatively and to moral identity positively. Furthermore, conformity orientation as another communication pattern and family social support correlated to aggression positively and to moral identity negatively. Family social support, conformity orientation and conversation orientation could account for 71% of variance in aggression. In addition, conversation orientation and family cohesion could account for 13% percent of variance in moral identity. The positive relationship between social support and aggression and its negative association with moral identity was contrary to expectations. Nevertheless, this study has confirmed the role of family variables in aggression and moral identity.