BACKGROUND AND OBJECTIVES: Many adolescents with type 1 diabetes experience diabetes-related distress (DRD; the negative emotional reactions specific to managing diabetes), but most research on DRD among adolescents relies on cross-sectional data. We assess adolescents' longitudinal DRD patterns and predictors of chronic DRD. METHODS: This secondary analysis of data from a depression prevention clinical trial included 264 adolescents with type 1 diabetes randomly assigned to a resilience or education intervention (mean age: 15.7 +/- 1.1 years; 59.8% female). Youth reported their DRD at 5 assessments over 16 months. Using latent class growth analysis, we classified adolescents into trajectory groups according to baseline starting point (intercept) and rate of change (slope) of DRD. We examined bivariate associations between trajectory group membership and demographic and clinical factors. Baseline predictors of chronic DRD were assessed via multiple logistic regression. RESULTS: Participants were classified into 4 groups: stable high DRD (7.2%; high intercept, flat slope), stable moderate DRD (28.0%; above-average intercept, flat slope), improving DRD (33.7%; average intercept, downward slope), and low DRD (31.1%; below-average intercept, downward slope). Lower hemoglobin A1c, greater adherence, fewer socioemotional difficulties, and more adaptive coping distinguished the improving and low DRD trajectories. Chronic DRD patterns were associated with female sex and higher depressive symptoms and hemoglobin A1c. CONCLUSIONS: In this study of adolescents' DRD trajectories during and after a psychoeducational intervention, one-third of youth were classified as having chronic, elevated DRD. Links with multiple clinical factors support efforts for routine DRD screening and comprehensive interventions for distressed youth.