Objective: Examine the relationship between self-efficacy and various measures of adiposity in a sample of teens. Methods: A total of 132 teens were selected from schools participating in an existing research study titled Teen Eating and Activity Mentoring in Schools (TEAMS). Teens completed demographic questionnaires and healthy eating–specific and physical activity–specific measures of self-efficacy. Waist circumference (WC), triceps skinfold thickness (TSF), and body mass index (BMI) percentile scores were also obtained. Results: Regression analyses indicated that healthy eating–specific and physical activity–specific measures of self-efficacy predicted WC and TSF. ANOVA revealed significant differences in healthy eating–specific self-efficacy levels between students of recommended weight and overweight/obese status. Supplemental analyses showed significant negative relationships between a student’s ideal BMI ratio and self-efficacy. Conclusions: Because self-efficacy may be amenable to change, these findings could inform future efforts aimed at increasing behaviors that promote healthy weight status among early adolescents.