Background: The Secret Agent Society (SAS) Program, an intervention to enhance social–emotional skills, was provided by schools for children with autism spectrum disorder (ASD). The program was assessed to determine if it improved social skills at school and home, and whether improvements were maintained. Methods: Eighty-four students participated. Key outcomes were parent and teacher ratings of emotion regulation, social skills, and direct child social problem-solving measures. The standard school curriculum served as the control condition. Phase 1 was a two-group waitlist-control comparison of SAS versus the standard curriculum. Phase 2 was a follow up of all participants before and after the intervention and at 12-months post-intervention. Results: Parent and child measures improved after the intervention but not in the waitlist condition. Improvements in parent, child, and teacher measures were apparent at 12 months. Conclusions: The SAS Program warrants further research as a potential program for schools that serve children with ASD. [ABSTRACT FROM PUBLISHER]