The aim of this study was to examine the causal relationship model of family environment and classroom environment with aggressive behavior at school through loneliness, non-conformist ideal reputation and attitude toward authority. The participants of this study were 343 of the second grade high school students of Poldokhtar public schools who were selected by multi-stage cluster random sampling. They completed "What is happening in this classroom?" Questionnaire, Family Environment Scale, The Aggression Scale, Loneliness Scale, Self-perception of Reputation, and Attitude to Institutional Authority Scale. In this study, the fitness of the proposed model was examined through path analysis. The findings indicated that proposed model by performing a modification showed good fitness with the data (c2/df=1.14, GFI=0.97, CFI=0.96, AGFI=0.94, IFI=0.98, RMSEA= 0.05). Also, the results showed that the family environment and the classroom environment through the influence of loneliness, attitudes toward authority, and non-conformist ideal were predictors of aggressive behavior at school. Based on these results, it can be claimed that aggressive behaviors can be predicted with respect to a variety of attitudes and feelings that a person is involved in family and the classroom.