Research suggests that children with autism spectrum disorders (ASD) have a prevalence of obesity at least as high as that seen in typically developing (TD) children. Many of the risk factors for children with ASD are likely the same as for TD children, especially within the context of today's obesogenic environment. However, the unique needs and challenges that this population faces may also render them more susceptible to the adverse effects of typical risk factors, and they may also be vulnerable to additional risk factors not shared by children in the general population. Psychopharmacological treatment, genetics, disordered sleep, atypical eating patterns, and challenges for engaging in sufficient physical activity may be uniquely associated with the development of obesity in children with ASD. Obesity and its associated sequelae potentially represent a significant threat to independent living, self-care, quality of life, and health for individuals with ASD. This article provides a summary of the literature on the prevalence of obesity in children with ASD and the putative obesity risk factors that this population may experience.