Objective: Sexual abuse experienced in childhood and adolescence is associated with severity of posttraumatic stress disorder (PTSD), depressive symptoms, and emotion regulation difficulties. The current study examined the relationships among these factors in a sample of adolescents with sexual abuse-related PTSD. It was hypothesized that (a) self-perceived emotion regulation difficulties would predict severity of PTSD and depressive symptoms, and that (b) depressive symptoms would mediate the relationship between emotion regulation difficulties and PTSD. Method: Ninety treatment-seeking female adolescents with a history of sexual abuse were evaluated using the Child PTSD Symptom Scale-Interview and completed the Negative Mood Regulation Questionnaire and the Beck Depression Inventory as part of a baseline evaluation. Results: Greater emotion regulation difficulties were associated with greater severity of PTSD and depressive symptoms. In addition, the relationship between emotion regulation difficulties and PTSD severity was mediated by depressive symptoms. However, the reverse was also true: the relationship between emotion regulation difficulties and depressive symptoms was mediated by PTSD symptoms. Conclusions: Mediation analyses showed that emotion regulation difficulties were associated with both PTSD and depressive symptoms rather than fitting a unidirectional model. These findings are consistent with and extend previous research and highlight the importance of emotion regulation in adolescent survivors of sexual abuse.