The current study examines the utility of self-trauma theory for explaining the long-term impact of childhood psychological abuse on aggression. Specifically, the self-capacities of interpersonal relatedness, identity, and affect regulation are tested as mediators of the impact of psychological abuse on various types of aggression in adulthood. Hierarchical regression analyses are used to examine data collected from 268 university students who completed the Personality Assessment Inventory, Comprehensive Child Maltreatment Scale, and the Inventory of Altered Self-Capacities. Results show that self-capacities were predicted by maltreatment, particularly psychological abuse. Altered self-capacities fully mediate the impact of child maltreatment on various forms of aggression. Problems with interpersonal relationships play the most significant role in mediating the relationship between child maltreatment and aggression. Results suggest more frequent maltreating experiences predict more dysfunctional self-capacities, which increases the probability of displaying various forms of aggression. (Contains 4 tables.)