Research on the impact of the classroom environment on neurotypical children has demonstrated that higher classroom quality contributes to children's development, but whether this is also true with regard to autistic preschoolers has not been examined. Therefore, the goal of this study was to address this gap hypothesizing that higher classroom quality would be associated with higher child social competence both in and outside the classroom. The quality of the classrooms of 43 autistic preschooler boys was assessed by observation, and children's social competence in preschool was assessed by observation and teacher-report, and outside preschool by observing children's interactions with an unfamiliar adult. Controlling for the severity of the boys' symptoms, results revealed that higher classroom emotional support and organization was associated with higher child social competence as observed and reported by teachers in preschool, and with the boys' involvement with of an unfamiliar adult during play. The quality of the classroom environment was associated with the social skills of autistic boys.