Irrespective of cultural identity or residential settings, different forms of aggressive behaviours are exhibited among groups of people. Aggressive behaviour is conceptualized as a form of behaviour directed to cause destructions, injuries, and harms to another individual. The main purpose of this study has to investigate the determinants of aggressive behaviour among Woldia university students. An institutional based -correlational design was employed to collect data using standardized questionnaire from 189 respondents through convenient sampling technique. Descriptive statistics such as mean, percentage, correlation test, and multiple regression model were used to analyse the determinant factors of aggression behaviour among students. The study revealed that the mean aggression score of students was (M, 73.04, SD, 16.70) which is very close to the scale mean. The bivariate correlation results showed that aggression is positively correlated with problematic social media use (r =.230, p<01) while it negatively correlated with sex (r = -.209, p <. 01), family relationships (r = -.283, p <. 01) and classroom environment (r = -.312, p <. 01). Results of the multiple linear regression showed that sex (β = --.157, t = - 2.278, p < .05) family relationships (β = -.185, t = -2.536, p < .05) and classroom environment (β = -.205, t = -2.810, p < .05) turned significant and negative predictors of aggression. From this it could be concluded that among the demographic variables sex and among the psychosocial factors family relationships and classroom environment are important determinants of aggression among university students. Based on the findings it was suggested among others that Woldia university in particular and all universities in general should establish or use their existing counseling centers to curb aggression, and parents should provide for warm and open relationship among family members including children to minimize possible development of aggression among their university students. Key words: Aggression, Empathy, family relationships, classroom environment, Problematic social media use