Social difficulties and symptoms of autism spectrum disorder (ASD) are frequently found in children with neurofibromatosis type 1 (NF1), a common genetic condition. The current study will examine (1) prevalence and characteristics of ASD and social impairment in children with NF1, (2) cognitive factors contributing to ASD symptoms and (3) associated compromise to brain structure. Findings are expected to guide development of treatments to improve social functioning in children with NF1.