To understand whose parenting (mothers vs. fathers) and which type of parenting (warmth vs. hostility) is more important in predicting adolescent aggression, this study applied dominance analysis to evaluate the relative importance of four different parenting dimensions (maternal hostility, paternal hostility, maternal warmth, and paternal warmth). Four waves of adolescent-reported longitudinal data from the PROSPER project (N = 626, 52% adolescent girls, 89% White rural, age 12 to 15) were used to investigate longitudinal change in the relative importance of these dimensions over time. Findings reveal that at most ages, maternal hostility was relatively more important than both paternal hostility and maternal warmth in predicting adolescent aggression among adolescent girls and boys. However, paternal parenting was more important for boys at specific ages. Findings are discussed in terms of implications for interventions and further research on parenting.