Pediatric obesity is associated with negative health and psychosocial consequences. However, obesity may not uniformly affect all populations. Limited research has investigated the factors that contribute to the incidence and persistence of overweight and obesity among children with autism spectrum disorder (ASD). This review systematically examined the prevalence rate of overweight and obesity among children with ASD. The majority of studies suggest that children with ASD may be at a greater risk for excess weight gain compared to typically developing peers. Additionally, this review investigated potential contributing factors to the etiology and maintenance of obesity within this population. Research should continue to investigate excess weight gain in this population in order to adapt weight loss interventions for children with ASD.