Individual differences are known to influence the risk of trauma exposure and development of posttraumatic stress disorder (PTSD). It has been suggested that features of autism spectrum disorder (ASD) may confer such risk. This article provides a systematic review of the assessment and treatment of PTSD in individuals with ASD, in addition to summarising the rates and presentation of PTSD within this population. Twenty-four studies met eligibility criteria. PTSD in children and adolescents was found to co-occur at a similar or greater rate compared to general population estimates, although current estimates come predominantly from treatment-seeking samples. Preliminary findings from case reports suggest traditional assessments and treatments for PTSD can be effective, although there is a shortage of well-controlled research.