Proactive and reactive functions of aggression are thought to manifest through different familial and emotional processes, even though they often co-occur. We investigated direct and indirect pathways through which maternal criticism and emotion regulation (ER) difficulties relate to reactive and proactive aggression in adolescence. Further, we examined how maternal criticism and emotion dysregulation interrelate, both concurrently and over time. Participants were 482 Dutch adolescents (M = 15.03, SD = 0.45, 57% boys) who self-reported on their ER difficulties, perceived maternal criticism, and reactive/proactive aggression. Cross-lagged panel modeling across four annual measurements revealed direct bidirectional links over time between maternal criticism and emotion dysregulation. Positive links over time from maternal criticism to proactive (but not reactive) aggression were also present. Emotion dysregulation and proactive aggression were linked only indirectly via maternal criticism. Gender did not significantly moderate these links. By revealing differential developmental pathways involving adolescents' ER and maternal criticism, the present study offers support for the dual function model of aggression. Aggr. Behav. 41:214-226, 2015.