The present study investigated the communicative characteristics of challenging behavior documented in children with Autism Spectrum Disorder (ASD), and how those behaviors changed as receptive and expressive language skills changed. Several years of the individual education plans (IEPs), behavior plans, and test scores of three male students from a small non- public school (NPS) were reviewed for this study. Challenging behaviors that served a communicative function showed some signs of diminishing as functional communication increased. While functional communication did show signs of increasing with the acquisition of expressive and receptive language the participants differed in their dependence on prompting to use functional communication in lieu of challenging behavior. Additionally, some of the challenging behaviors were rooted in a difficulty with self-regulation and stimming behavior and didn't appear to serve a communicative function. Given the significant impact challenging behaviors have on the quality life of the children with ASD and their families, more research is needed to better understand the connection between spontaneous and independent functional communication and duration to independent attention to task effects on challenging behavior.