The present study examined the influence of family and classroom environments on the development of particular individual characteristics, including level of empathy, attitude to institutional authority and perceived social reputation, and the role these characteristics may in turn play in school aggression. Participants were 1319 adolescents aged 11-16 (47% male) drawn from state secondary schools in Valencia (Spain). Since previous studies suggest that these variables may contribute differentially to aggressive behaviour depending on adolescent gender, two different mediational structural models were calculated, respectively, for boys and girls. Results obtained confirmed the associations expected among the variables considered in the structural equations tested and pointed out different paths for boys and girls. Overall, our findings suggested that a positive family environment seems to be a stronger protective factor for girls in the development of problems of behaviour at school, whereas for boys this is the case for a positive classroom environment. This model accounted for 40% of the variance in aggression at school for boys and 35% for girls.