This document discusses social skill development and deficits in social skills that are often seen in autism spectrum disorders (ASD). It addresses several theories of social development and then defines six areas of social skill deficits in ASD, including difficulties with social-emotional reciprocity, nonverbal communication, relationship development and maintenance, stereotypical behaviors, adherence to routines, and sensory reactivity. Examples are provided to illustrate challenges with social communication, social initiation, social reciprocity, and social cognition that individuals with ASD may face. References are included at the end.