Students with autism spectrum disorder (ASD) often experience peer conflict and social challenges, which likely relate to compounded characteristics of both the child with ASD and his or her peers. However, few studies have experimentally investigated these associations to inform prevention and intervention efforts. The present study used social networking blogs to examine how middle school students’ attitudes toward a fictional peer with ASD, Charlie, vary according to whether Charlie was (a) physically included with typically developing peers and (b) socially accepted. Participants expressed less favorable attitudes when Charlie was socially excluded by his peers, regardless of whether his peers had disabilities. More favorable attitudes were associated with participant popularity, previous exposure to ASD, younger age, and being female. Charlie’s ASD status was associated with more negative anticipated peer attitudes. These results indicate that facilitating positive, public social experiences of students with ASD may promote positive attitudes and social acceptance by peers.