The assessment of individuals with autism spectrum disorder (ASD) at the prelinguistic stage of communication development requires a comprehensive approach. Standardized assessments can contribute valuable information to the evaluation of each individual’s strengths and needs, from screening through to diagnosis, treatment planning, and treatment evaluation. However, using standardized assessments with this population can be challenging, given that many assessments require the individual to have symbolic communication skills. In this chapter, we outline the components of a comprehensive assessment, discuss the ways in which standardized assessments can inform clinical decision making, and provide recommendations to address the common challenges associated with using standardized assessments with prelinguistic individuals with ASD.