Although there are many similarities between individuals with autism spectrum disorder (ASD), the population is extremely heterogeneous. Each individual with ASD has a unique mix of behavioral, communicative, social and/or cognitive differences that require therapeutic intervention. This makes assessment of ASD difficult as practitioners must evaluate a wide range of behaviors across social contexts, to decide if an individual falls on the autism spectrum. The recent reported increase in ASD has created a growing demand for research examining how evidence-based practices (EBPs) developed for children with ASD can be effectively disseminated into community programs. Although consistency and reliability for ASD assessment practice has been established in the research community, it is unclear how ASD is being assessed in community settings such as schools. This study evaluated the benefits of school psychologist use of EBP for ASD evaluations. A multiple baseline design was conducted across six school psychologists who collectively assessed 77 children for ASD over the course of the study. After a baseline phase where usual care for assessment of children with ASD in the school setting was monitored, school psychologists were trained to utilize two standardized ASD assessments that are considered EBP for ASD evaluation in research settings: the Autism Diagnostic Observation Schedule (ADOS) and the Social Communication Questionnaire (SCQ). The findings of this study add support for the value of school psychologist training in EBP for ASD evaluation. The school psychologists were easily able to adopt most of the EBP assessment techniques introduced to them over the course of the study with relatively little training. The EBP training they received changed their ASD evaluation process such that after training they were more likely to adhere to EBP guidelines for ASD evaluation. In turn, this adherence to EBP guidelines resulted in identification of more ASD-specific behaviors in the children they assessed. This study is the first of its kind to systematically examine school psychologist adoption of EBP for ASD evaluation, specifically the ADOS and SCQ, in the school setting