ABSTRACT Objectives To examine the relationship between social support and aggression among male juvenile delinquents and the mediating role of mindfulness and self-control/impulsivity. Methods A total of 530 male juvenile delinquents completed the Social Support Rating Scale, the Mindful Attention Awareness Scale, the Self-Control Scale, the Aggression Questionnaire, and the Barratt Impulsiveness Scale. Results The total effect of social support on aggression was significant (β= −0.24, p < 0.001, Bootstrap 95%CI[−0.38, −0.19]). Social support affected individual aggression through the following five paths: (1) social support → trait mindfulness → aggression (Bootstrap 95%CI[−0.07, −0.01]); (2) social support → self-control → aggression (Bootstrap 95%CI[−0.18, −0.08]); (3) social support →impulsivity → aggression (Bootstrap 95%CI[−0.12, −0.05]); (4) social support → trait mindfulness → self-control → aggression (Bootstrap 95%CI[−0.07, −0.01]); (5) social support → trait mindfulness →impulsivity → aggression (Bootstrap 95%CI[−0.03, −0.01]), indicating that these five mediating effects were significant. Conclusions It suggests that social support is associated with aggression among male juvenile delinquents. Social support is negatively correlated with aggression through multiple mediating effects of mindfulness, self-control, and impulsivity.