Children with autism spectrum disorder (ASD) have difficulties interacting with same-aged peers during unstructured play (e.g., on the playground). Thirty-five toddler and preschool children with and without ASD participated in a structured 15-min outdoor play curriculum. The intervention, the Buddy Game, used familiar songs, movement, and games to promote peer social interaction. A 2 × 3 ANOVA assessed changes in overall targeted social behaviors during baseline, the Buddy Game, and generalization to free-pay. Multiple regression analyses examined factors related to increases in social interactions. Predictors were ASD status of child and age of child. Results indicated the Buddy Game increased overall social interactions and that social interactions were influenced more by ASD status than age. Implications for practitioners are highlighted.