A community sample of 167 elementary school students was evaluated in order to examine the relationship between trajectories of indirect and direct peer victimization and perpetration with externalizing and internalizing problems. While eight models were proposed, only six were tested. Four of these models focused on the perpetration of peer aggression. Results indicated that the perpetration of direct peer aggression in the fall of children's kindergarten year predicted externalizing behaviors in the spring of first grade; however, the perpetration of direct peer aggression was not observed to predict internalizing problems. The perpetration of indirect peer aggression in the fall of kindergarten was found to predict internalizing behaviors in the spring of first grade, though predictions of externalizing problems were not significant. Two models focused on peer victimization. Results indicated that victimization by direct peer aggression were not significantly predictive of externalizing or internalizing problems. Gender differences in these findings were also investigated. Overall, the results of the present study show that victimization by peer aggression and perpetration of aggression toward peers are common in early childhood, and suggest that aggression toward peers may play a particularly salient role in the development of later adjustment problems.