Background: Psychopathology demonstrates marked changes within and between individuals across development, especially during the transition from childhood to adolescence. Evidence characterizing the directionality and rate of change across distinct dimensions of psychopathology has been mixed, with different studies indicating increases, decreases, or no change in internalizing and externalizing symptoms. Moreover, much remains unknown about the extent to which trajectories differ across individuals. Methods: Using a large, diverse national sample of youth (9-10 years old at baseline) from the Adolescent Brain Cognitive Development (ABCD) Study® (n = 6,405) we tested trajectories of psychopathology over three years. At each time point, parents reported their child’s internalizing and externalizing symptoms. Results: Results from a latent growth curve model indicated that, on average, externalizing symptoms decreased across the three time points, whereas internalizing symptoms did not significantly change. We then used growth mixture modeling to identify latent subgroups of pre-adolescents with distinct psychopathology trajectories. Results indicated that there were four different internalizing trajectories: a high-stable group, a moderate-decreasing group, a moderate-increasing group, and a low-decreasing group. For externalizing symptoms, there were three trajectories: a high-decreasing group, a moderate-increasing group, and a low-decreasing group. We also used parallel process growth analysis to examine the co-development of internalizing and externalizing symptoms and identified five subgroups with distinct patterns of co-development. These subgroups were differentially associated with sex and age. Conclusion: These findings highlight important heterogeneity in the development of psychopathology during pre-adolescence.