Prevalence rates for autism spectrum disorders (ASD) have risen dramatically in recent years and children are being identified earlier (i.e., under the age of 3). This has placed pressure on state early intervention systems to serve young children with ASD. However there are few treatment models available that are both feasible across different types of community settings and have demonstrated effectiveness. The overarching purpose of the current project is to conduct a randomized trial to evaluate the efficacy of a previously developed and pilot-tested model for very young children with ASD called Project DATA (Developmentally Appropriate Treatment for Autism)–Toddler. The major goals will be to examine whether children receiving this intervention show greater gains in cognitive functioning, language, social relatedness, and adaptive behavior; whether parents of these children demonstrate gains in recommended parenting strategies and decreased stress; and whether the intervention is acceptable in terms of general satisfaction and ability to work effectively within the context of different cultures. The ultimate aim of the research is to enable feasible and beneficial community-based services for toddlers with ASD. In this study, each child and their caregiver(s) will be randomly assigned to either the experimental condition (DATA–Toddler) or a comparison condition (standard care). After an intensive week-long training for the interventionist, follow up monitoring (fidelity checks) is scheduled weekly for the first four weeks to ensure appropriate implementation. Child assessments and parent reports will be administered pre-intervention and quarterly thereafter, including measures of symptoms, cognitive functioning, language, problem behavior, social behavior, engagement, and parent and family stress. Measures of adaptive behavior, family routines, and received child services will be collected at baseline and post-treatment. Products from this project will include published reports and presentations on the efficacy of DATA–Toddler.