The purpose of this review was to critically examine and summarize the impact of school-based interventions designed to decrease challenging behaviors in young children with Autism Spectrum Disorder (ASD). Reviewed studies employed a single-case experimental design, targeted challenging behaviors, included children 3-8 years old with ASD, and took place in school settings. Interventions were categorized as antecedent-based, function-based, reinforcement, instructional, or multicomponent. In addition to analyzing articles descriptively, effect size estimates were calculated using the Non-overlap of All Pairs and Tau-U methods. A total of 26 studies including 44 children were reviewed. Individual effect size estimates ranged from weak to strong, but on average, the reviewed interventions were effective in decreasing the target behaviors exhibited by the participants. Findings suggest that interventions implemented in school settings can effectively decrease challenging behaviors exhibited by young children with ASD. Directions for future research and practice are also discussed.