Physicians have an important role addressing the obesity epidemic. Lack of adequate teaching to provide weight management counseling (WMC) is cited as a reason for limited treatment. National guidelines have not been translated into an evidence-supported, competency-based curriculum in medical schools. Weight Management Counseling in Medical Schools: A Randomized Controlled Trial (MSWeight) is designed to determine if a multi-modal theoretically-guided WMC educational intervention improves observed counseling skills and secondarily improve perceived skills and self-efficacy among medical students compared to traditional education (TE). Eight U.S. medical schools were pair-matched and randomized in a group randomized controlled trial to evaluate whether a multi-modal education (MME) intervention compared to traditional education (TE) improves observed WMC skills. The MME intervention includes innovative components in years 1-3: a structured web-course; a role play exercise, WebPatientEncounter, and an enhanced outpatient internal medicine or family medicine clerkship. This evidence-supported curriculum uses the 5As framework to guide treatment and incorporates patient-centered counseling to engage the patient. The primary outcome is a comparison of scores on an Objective Structured Clinical Examination (OSCE) WMC case among third year medical students. The secondary outcome compares changes in scores of medical students from their first to third year on an assessment of perceived WMC skills and self-efficacy. MSWeight is the first RCT in medical schools to evaluate whether interventions integrated into the curriculum improve medical students' WMC skills. If this educational approach for teaching WMC is effective, feasible and acceptable it can affect how medical schools integrate WMC teaching into their curriculum.