The prevalence of autism spectrum disorders (ASD) has grown dramatically in recent years, with advances in early identification now resulting in an influx of toddlers to the early intervention system. Although early intervention providers are required to implement evidence-based practices for this population, few models are available that target social communication, the core difficulty in ASD, at the preverbal stage when neurological development is most malleable. The proposed project directly addresses this need through an efficacy study of Joint Attention Mediated Learning (JAML), an intervention practice for toddlers with ASD that directly targets foundational preverbal social communication competencies from within the parent-child relationship at a critical juncture (by 30 months of age). Specifically, this study will determine the efficacy of JAML on the early preverbal and verbal social communication development of toddlers with ASD and the self-efficacy of their caregivers, assess factors that mediate and moderate intervention effects, and address the feasibility and acceptability of JAML. Researchers will conduct a randomized controlled trial that compares the JAML intervention to a business-as-usual condition. The research team will recruit 126 toddlers, aged 30 months or younger, with ASD. Assessments will be conducted prior to the intervention (pre-test), post-intervention (post-test), and 6 months after the post-test to measure the sustainability of any intervention effects. This study will take place in family homes in rural, suburban, and urban areas in Indiana, Kansas, and North Carolina.