Considering the detrimental effects of adolescent aggression on their development, the present study was undertaken to investigate the relationship between family functioning, the quality of interpersonal relationships, and socio-economic status with the level of aggression among high school students. The research method was descriptive and correlational. The participants were 316 high school students from Tabriz during the first semester of the 2015-2016 academic year, selected through multi-stage cluster sampling. They completed the Buss and Perry Aggression Questionnaire (1992), the McMaster Family Assessment Device (1983), the Quality of Relationship Inventory by Pierce et al. (1991), and a researcher-made socio-economic status tool. The data were analyzed using SPSS-23 software. The results demonstrated a significant relationship between the components of family functioning, interpersonal relationships, and the level of adolescent aggression. Family functioning and interpersonal relationship dimensions could predict changes in the level of aggression. However, no significant relationship was found between socio-economic status and the dimensions of adolescent aggression. Since family functioning and interpersonal relationship dimensions can explain the level of adolescent aggression, improving these variables can reduce adolescent aggression.