Objective: The negative impact of caring for a child with autism spectrum disorder (ASD) on parents' psychophysiological functioning has been widely evidenced. However, siblings, who also face emotional, social and physical challenges associated with having a brother/sister with ASD, have been less widely studied. This study examined the psychophysiological impact of childhood ASD on Siblings of children with ASD experience greater emotional problems and overall depressive symptoms compared with a control group. Interventions that enhance social support, as well as helping siblings better understand the behaviour problems of their brother/sister with ASD, might be effective for alleviating depressive symptoms.