ABSTRACT Approximately 50% of children with autism spectrum disorder (ASD) exhibit disruptive behaviors such as tantrums, aggression, and noncompliance that significantly impact meaningful engagement in academic tasks and with peers as well as result in placement in more restrictive classroom settings. Current school-based behavioral management approaches, while effective, are time-consuming and resource-intensive. There is a need for efficient and pragmatic intervention models that build capacity with direct care providers, streamline the intervention process, reduce the need for intensive behavioral supports, and increase the number of children with ASD who can be served. The RUBI program is an evidence-based parent-mediated intervention that improves disruptive behavior in children with ASD. Considering schools serve as the primary intervention setting for children with ASD, and paraeducators often struggle to address challenging behavior in the classroom, there is an opportunity to meaningfully improve care by moving RUBI from delivery in clinic to school and from parent to paraeducator. The current study is an extension of a recently completed NIMH- funded human-centered design study targeting modification of RUBI to ensure its appropriateness for use in educational settings. The proposed three-year pilot randomized trial aims to test the effectiveness of the newly- redesigned paraeducator-delivered RUBI for use in Educational Settings (RUBIES) intervention compared to usual care training in reducing disruptive behavior in 80 elementary-school children with ASD. Given the critical need to understand not just whether, but also how interventions work, this study also will examine paraeducator- and child-level mechanistic pathways of the RUBIES intervention. Successful completion of the proposed study will allow for a large-scale effectiveness trial of RUBIES in public schools to reduce disruptive behavior, which has the potential to improve the quality of life for children with ASD across the country.