Parents' cognitive schemas about parenting, personal vulnerabilities, and personal resources may affect their risk of engaging in parent-child aggression (PCA). This longitudinal study examined predictors of change in mothers' and fathers' PCA risk across the transition to parenthood, comparing trajectories of parents evidencing high versus low sociodemographic risk. Potential predictors involved parenting-relevant schemas (consistent with Social Information Processing theory, including approval of PCA, negative attributions of child behavior, and knowledge of nonphysical discipline options), personal vulnerabilities (psychopathology, intimate partner violence, substance use issues), and resources (problem-focused coping, emotion regulation, social support, and partner satisfaction). Results indicated that increases in PCA approval, negative child behavior attributions, and symptoms of psychopathology, as well as decreases in problem-focused coping skills, emotion regulation ability, and partner satisfaction, all significantly predicted changes in mothers' and fathers' PCA risk over time—regardless of risk group status. Notably, increases in intimate partner violence victimization and decreases in social support satisfaction predicted mothers' but not fathers' PCA risk change; moreover, increases in knowledge of nonphysical discipline alternatives or in substance use issues did not predict change in PCA risk for either mothers or fathers. Risk groups differed in PCA risk across all predictors with minimal evidence of differential trajectories. Overall, these findings have important implications for child abuse prevention programs involving both universal and secondary abuse prevention efforts.