Existing randomized controlled trials of family therapy for treatment of bulimia nervosa in adolescence highlight the need for further development of treatments. This article describes the development of multi-family treatment for bulimia nervosa in adolescents aged 13-18. It outlines the theory guiding this development, the areas of need identified by previous studies, and the treatment that has been designed to meet these needs. Particular attention is given to the need to increase communication between family members, strategies to reduce high levels of criticism or hostility, and skills to manage emotion dysregulation and low tolerance for negative emotions. To these ends the program draws on the multi-family treatment for anorexia nervosa, cognitive behavioral therapy techniques, and dialectical behavior therapy.