The role of rumination in the development and maintenance of psychopathology has been well established. Far less is known however, about possible precursors to this repetitive thinking style. The current study examined two potential developmental antecedents of rumination: insecure attachment and affect regulation. Reports of attachment anxiety and avoidance with maternal figures were examined as predictors of both sadness and anger rumination in a sample of high-risk youth. Affect dysregulation and suppression were also assessed as potential mediators of these associations. Participants completed questionnaires at three time points within a five-year period, with the current study examining associations concurrently at Time 1 and prospectively across Time 2 and 3. Gender differences in these relationships were also assessed. Participants at Time 1 were 159 adolescents (84 males, 75 females) between the ages of 12 and 18 years (M = 15.41, SD = 1.52). Concurrent and prospective associations were tested within a path analysis framework. With respect to concurrent relationships at Time 1, statistically significant associations were found between affect dysregulation and anger rumination for females and males. The association between anger rumination and attachment anxiety was small to moderate, and not statistically significant. Associations between sadness rumination and both attachment avoidance and affect suppression were also not statistically significant for either gender. When examining relationships across time, attachment anxiety significantly predicted increased anger rumination only in females. Affect dysregulation was significantly associated with higher levels of anger rumination for both females and males. Despite this, affect dysregulation did not mediate the association between attachment anxiety and anger rumination. With respect to sadness rumination, attachment avoidance was found to be a significant predictor in females. Implications of these findings for preventative and intervention efforts are discussed.