Several researchers have employed milieu therapy to address the communication needs of children with autism spectrum disorder (ASD). Thus, the purpose of this review is to examine milieu therapy, particularly, the environments and individuals involved in the training and the effectiveness of milieu therapy with children who have a diagnosis of ASD and to provide suggestions for practitioners and researchers. Milieu therapy consistently increases communication and generalizes to other settings, while maintaining over time; however, milieu therapy does not analyze connections to challenging behaviors and few studies have focused on teachers in the classroom or peers. Future research teams should continue to train parents and teachers while addressing the connection to challenging behavior and including peers in the interventions. (Contains 4 tables.)