Psychoeducation has been the only group treatment developed for bipolar disorder thus far. Deficits in emotion regulation, a core impairment among patients with bipolar disorder, are not directly addressed in this treatment. The objective of this study is to develop a group treatment for bipolar disorder that focuses on emotion regulation strategies (Enhancing Emotion Regulation; EER). This study will examine the efficacy of this treatment using an open trial design. It is hypothesized that patients who receive EER will show a reduction in mood symptoms and improvement in well-being. Reductions in emotion regulation difficulties will predict improvements.