Background: Childhood obesity is a major public health concern. Children with disabilities have a higher prevalence of obesity. Objective: We examined factors associated with obesity within a cross-sectional study of US adolescents with and without disabilities. Methods: Data were obtained from the 2011 Youth Risk Behavior Survey. Logistic regression models were fitted to assess effects of dietary habits, physical activity, and unhealthy weight control behaviors on obesity. Effect modification by disability status was examined. Results: Twenty percent (1986 of 9775 participants) reported a disability. Adolescents with disabilities were more likely to be obese (odds ratio [OR] = 1.7; 95% confidence interval [CI]: 1.3-2.1) and have at least 1 unhealthy weight control behavior (OR = 2.0; 95% CI: 1.6-2.5), and were less likely to be physically active (OR = 0.5; 95% CI: 0.4-0.6). Lack of physical activity, increased television watching/video game playing, and unhealthy weight loss behaviors were significantly associated with obesity regardless of disability status (p-for-interaction >0.05). Conclusions: Successful obesity interventions should target diet, physical activity, and weight control among adolescents with disabilities. Understanding barriers to healthier diet and physical activity for this population is critical to developing effective obesity prevention programs and reducing the prevalence of unhealthy weight control behaviors.