Parents of children with autism spectrum disorders (ASD) reported higher stress than those of typically developing children. The role of child problem behaviors in the relationship between autism spectrum symptoms and parenting stress is little known. A total of 731 parents of 177 children with ASD and 554 typically developing children in primary schools (6-11 years old) completed an ASD screening survey containing measures of parenting stress and child problem behaviors. While autism spectrum symptoms were positively associated with parenting stress, the relationship was mediated by child problem behaviors. Results suggest neither the severity of autism spectrum symptoms nor knowledge of ASD diagnosis was a primary source of parenting stress. A hypothesized path model was tested using structural equation modeling.