The purpose of this study was to develop an Internet coping skills training program and to evaluate its feasibility and acceptability compared with an Internet education intervention for teenagers with type 1 diabetes. A multiphase mixed-methods design with focus groups, a randomized pilot study, and a program evaluation was used. Teenagers with type 1 diabetes, parents, and health professionals were included in the development and evaluative phases along with the research and information technology team. The pilot study included 12 teenagers with type 1 diabetes (mean [SD] age, 14.4 [.90] years; 58% female; mean [SD] duration of diabetes, 5.9 [3.0] years). Psychosocial data and HbA1c levels were collected at baseline and at 3 and 6 months. Results indicate that the development of a psychosocial Internet intervention was complex and required multiple iterations of development and evaluation. Results of this study also indicate the feasibility and acceptability of translating a group-based intervention for teenagers with type 1 diabetes to the Internet. Thus, this study demonstrates a systematic approach to Internet intervention development. Including teenagers with type 1 diabetes and a multidisciplinary professional team into the intervention design was critical to the success of this project.