Despite strong consensus that early, specialized intervention for children with autism spectrum disorder (ASD) can have a dramatic impact on outcomes, the public health system's capacity to provide such services is severely challenged by the rapid rise in ASD prevalence. The goal of this research project is to increase timely and equitable access to ASD-specialized early intervention during the critical first three years of life by capitalizing on the existing infrastructure of the Part C Early Intervention (EI) system, which is publicly funded and available in all states in the United States. This project will train EI providers to use an evidence-based, parent-mediated intervention that can improve child and family outcomes as well as mitigate the long-term substantial economic costs associated with ASD.