Research shows that children with developmental disabilities, such as autism spectrum disorder (ASD), are at significantly increased risk for adverse childhood experiences (ACEs) and traumatic experiences. Children and families impacted by ASD possess several identifiable risk factors which further amplify their risk for ACEs. There are several characteristics of ASD that may exacerbate posttraumatic stress symptoms in this population, such as pre-existing anxiety-related conditions and poor emotion regulation abilities. However, identifying posttraumatic stress symptoms in this population is difficult due to broad overlap between posttraumatic stress and ASD-related symptoms that leads to diagnostic overshadowing. The current study measured symptoms of posttraumatic stress and social impairment in children with ASD who experienced ACEs and compared them to children with ASD without ACEs and typically developing children with ACEs. Results found that children with ASD who experienced ACEs demonstrated greater rates of comorbid diagnoses of ADHD, depression, and anxiety and demonstrated significantly higher rates of posttraumatic avoidance, depression, anger/aggression, and overall posttraumatic stress compared to children with ASD without ACEs. They did not demonstrate increases in ASD-related symptoms of social impairment as a result of ACEs. ACEs type was predictive of posttraumatic stress symptoms in several domains. In typically developing children, a high number of accumulated ACEs was predictive of clinically significant symptoms of social impairment that may contribute to the diagnostic ambiguity between ASD and posttraumatic stress response to ACEs in children.