ABSTRACT Mothers of adolescents with type 1 diabetes experience high levels of depressive symptoms, which impair their ability to monitor and manage diabetes treatment effectively. Given that adolescents are a high-risk population for suboptimal glycemic control – with only 17% meeting treatment goals - there is a critical need for novel interventions to improve outcomes in adolescents with T1D. Yet, previous behavioral interventions for youth with diabetes have not directly targeted maternal depressive symptoms. Building on effective interventions to treat depression in adults, and our own pilot work in this population, the proposed study will use a rigorous approach to evaluate the efficacy of a cognitive-behavioral intervention for mothers of adolescents with type 1 diabetes to promote the use of adaptive coping strategies and positive parenting practices. Results from our pilot study indicated significant intervention effects on adolescents’ quality of life and depressive symptoms. In addition, adolescents whose mothers received the intervention demonstrated promising improvements in glycemic control, and we found support for the effect of the intervention on mediating variables, with large effects on maternal depressive symptoms and family conflict. The revised aims of this study are to: 1) evaluate the effects of the Communication & Coping intervention on diabetes-related outcomes; 2) evaluate the effects of the Communication & Coping intervention on psychosocial outcomes; and 3) explore the differential impact of the intervention across demographic factors. Mothers who are randomized to the Communication & Coping Intervention will receive individual cognitive-behavioral therapy sessions by phone, as well as access to a Facebook group to augment the material covered in calls and provide social support. Mothers randomized to the Attention Control condition will receive educational materials and phone check-ins, as well as a Facebook group with educational posts. Adolescents and their mothers will be assessed at baseline and again post- intervention, at 3 months, 6 months, and 12 months. We hypothesize that the adolescents of mothers who receive the intervention will demonstrate improvements in diabetes outcomes (i.e., glycemic control, adherence), as well as psychosocial outcomes (i.e., improved quality of life, fewer depressive symptoms) compared to those in the attention control condition. This approach is innovative by targeting maternal depressive symptoms and the quality of parental involvement in mothers of adolescents with type 1 diabetes. Responding to the American Diabetes Association’s call to address the psychosocial needs of people with diabetes and their family members, the proposed project has the potential to improve outcomes in both adolescents with type 1 diabetes and their mothers.