Research has found that depression is more common among individuals with diabetes and is associated with worse diabetes outcomes including treatment nonadherence, worse glycemic control, higher risk of diabetes complications, greater functional impairment, and increased risk of mortality. These patterns of association have led to an increase in research investigating the relationship between diabetes and depression. There remain important questions about the relationship between depression and diabetes and an unmet need for treatment approaches that are successful in ameliorating depression and improving diabetes outcomes. The current commentary discusses several conceptual issues related to the measurement of depression in diabetes, argues for the importance of health behavior and treatment adherence in approaching the problem of depression in diabetes, and provides an example of a treatment approach that incorporates the treatment of depression with strategies aimed at improving treatment adherence in order to maximize effects on diabetes outcomes.