Despite evidence documenting the negative consequences, psychological dating violence occurs frequently in adolescent dating relationships. No information exists on the trajectories that adolescents follow and their association to nonphysical peer violence. The sample comprised 624 randomly selected 6th graders. In yearly surveys from 6th through 12th grade, 550 of the 624 students reported dating at least twice during the 3 months prior to completing the survey. These students responded to questions about frequency of engagement in psychological dating violence perpetration and victimization. We used Proc TRAJ to identify developmental trajectories of behavior over time and generalized estimating equation models to examine the associations of the trajectories and peer aggression. Adolescents followed three distinct developmental trajectories related to psychological dating violence victimization and perpetration: low, increasing, and high. Based on the joint probabilities of victimization and perpetration, we identified four predominant groups: low victimization/low perpetration (LVLP; 36%), increasing victimization/increasing perpetration (40%), high victimization/high perpetration (HVHP; 15%), and increasing victimization/low perpetration (IVLP; 7%). The LVLP had significantly more boys and White students; the HVHP group had an even gender distribution and more African-American students. For all groups, peer aggression decreased from Grade 6 to 12; students in the HVHP group reported the highest peer aggression, and students in the LVLP reported the lowest peer aggression. Findings suggest a strong, reciprocal relationship in the developmental trajectories of adolescents who experience and perpetrate psychological dating violence. Those highly engaged in these behaviors were also more likely to be violent toward peers. Aggr. Behav. 38:510-520, 2012. © 2012 Wiley Periodicals, Inc.