Being in a caregiver role for a child with autism spectrum disorder (ASD) brings a unique set of stressors and challenges to the entire family unit. This study examined a model hypothesizing that (a) parenting stress and the parenting style used by the parents of a child with ASD are correlated; (b) ASD severity, parenting stress, and parenting style uniquely explain the variance in the presentation of internalizing and externalizing symptoms among children with ASD; and (c) parenting style moderates the association between ASD severity and the presentation of internalizing and externalizing behaviors after controlling for specific demographic variables. A group of online participants were recruited through personal contacts, social media, and Amazon's Mechanical Turk. The group of subjects, made up of 70 primary caregivers of children ages 3 to 18 years diagnosed with ASD, completed a self-report measure. Statistical analyses revealed that ASD severity and parenting style contributed to externalizing behaviors but did not have a significant impact on internalizing behaviors. Parenting stress was the primary predictor of both internalizing and externalizing child behaviors. Parenting style was not related to the stress level of parents of children with ASD and was not found to moderate the relationship between ASD severity and internalizing and externalizing behaviors. Implications for future research and clinical practice are discussed, highlighting the importance of reducing parenting stress and providing parent training to promote positive parenting styles for children with ASD.