This study examined associations between perceived popularity trajectories and changes in proactive and reactive aggression in middle adolescence. The sample included 1,374 adolescents from 5 cohorts who were followed from Grade 7 to Grade 9 (49% males, Mage = 12.67 years, SD = .67). Popularity trajectories were identified based on initial status and changes in status over time, and linear mixed effects models tested group differences in changes of aggression. The results partially confirmed our expectation that changes in popularity were associated with specific developmental patterns of proactive and reactive aggression and also varied as a function of status already achieved. Specifically, adolescents in groups characterized by gains in status increased in proactive aggression, and those in groups characterized by losses in status decreased in proactive aggression. A more nuanced pattern of group differences emerged for reactive aggression. Changes in reactive aggression were only found for groups characterized by changes in unpopular status. Taken together, these findings suggest that proactive aggression has universal benefits for popularity in middle adolescence, whereas reactive aggression has differential costs. Implications and directions for future research are discussed. (PsycINFO Database Record (c) 2019 APA, all rights reserved).