Mothers of adolescents with type 1 diabetes (T1D) experience high rates of depressive symptoms and diabetes distress, which are established risk factors for deteriorating glycemic control, problems with adherence, increased depressive symptoms, and poor quality of life in adolescents. Given that adolescents are a high-risk population for suboptimal glycemic control, novel interventions to improve outcomes in adolescents with T1D are needed. Building on effective interventions to treat depression in adults, and our own pilot work in this population, we developed a cognitive behavioral intervention, Communication & Coping, to target maternal depressive symptoms and parenting behaviors. The randomized controlled trial compares the telephone and Facebook-delivered Communication & Coping intervention, which promotes the use of adaptive coping strategies and positive parenting practices, to a diabetes education control condition on diabetes outcomes and psychosocial outcomes in adolescents with T1D. This paper describes the study rationale, trial design, and methodology.