Autism Spectrum Disorder (ASD) is a developmental disorder that impacts functioning in the core areas of social communication and interaction and secondly, restrictive, repetitive patterns of behaviors and interests. In the past, Aspergers’ Syndrome and Pervasive Developmental Disorder were considered separate conditions, but in the advent of the DSM-5, are now considered part of the Autism Spectrum. Children, teens and young adults with ASD often experience difficulties with anxiety that can include excessive worry, anticipatory anxiety, phobic reactions to feared situations, sounds or sensations and social anxiety. Difficulty with reading the social environment and difficulty with being flexible can make it very hard for those with ASD to handle changes in routine, friendships, and daily challenges. Frequently, children and teens with ASD experience school refusal, oppositional behavior, failure to launch, and failure to make and keep friends, despite being able to make good grades. Many children with Autism Spectrum Disorder have one or more types of anxiety disorders. Research has demonstrated that anxiety disorders exacerbate the social difficulties and other functional impairments caused by ASD. Anxiety may worsen during adolescence, as young people face an increasingly complex social milieu and often become more aware of their differences and interpersonal difficulties.