Current standards for identifying quality early childhood programs (e.g., NAEYC, ECERS) provide guidance on classroom play materials, but little research has focused on the interface between toy selection and arrangement and its effects on children’s behavior and social interactions. This study examined the effects of toy selection and arrangement on four positive and five negative social behaviors of 15 preschoolers in an inclusive classroom for children with autism and typically developing children. Three conditions were under investigation (a) conventional material package, featuring items recommended by teachers in NAEYC accredited programs, (b) systematic materials package developed to include sensory preferences and logistical considerations, and (c) enhanced materials package that featured more frequent rotation of items. Results indicate that systematic material selection and arrangement is significantly related to increased frequency of several positive social behaviors and decreased frequency of negative behaviors. The systematic and enhanced materials packages were superior to the conventional package for all variables studied. In summary, embedding systematic arrangements of toys and play materials into existing standards for high quality early childhood classrooms yielded desirable improvements in the social behaviors of all children in an inclusive classroom.