In this study, we investigate peer relationships and participation in social and recreational activities among 235 adolescents and adults with autism who live at home. The prevalence of having friendships, peer relationships, and participating in social and recreational activities were all low and comparable to previous research. Both individual and environmental factors were investigated as predictors of having peer relationships and participation in social and recreational activities. Having peer relationships was predicted by individual characteristics (younger age, and less impairment in social interaction skills), but not by characteristics of the environment. Greater participation in social and recreational activities was predicted by characteristics of the individual with autism (greater functional independence, less impairment in social interaction skills, higher levels of internalizing behaviors) and characteristics of the environment (greater maternal participation in social and recreational activities, greater number of services received, and inclusion in integrated settings while in school).