Overweight in adolescents has nearly tripled in the past two decades and has serious physical and psychosocial consequences, both during adolescence and into adulthood. School nurses have tremendous potential to prevent and treat overweight in this population, as over 95% of adolescents have contact with the school health system each year and school nurses have the credibility and skills to provide guidance regarding weight, diet and physical activity. The goals of the proposed exploratory study are to adapt an innovative, theory-based school nurse-delivered counseling intervention model used effectively for smoking cessation for the treatment of adolescent overweight, and test its feasibility and potential efficacy in reducing BMI, improving diet, increasing physical activity and decreasing sedentary behavior. If the results of this exploratory study prove promising, the efficacy of the intervention will be evaluated in a large scale randomized controlled trial.