This article reviews the "Autism Diagnostic Observation Schedule, Second Edition" (ADOS-2; Lord, Luyster, Gotham, & Guthrie, 2012; Lord, Rutter et al., 2012), a newly updated, semistructured, standardized measure of communication, social interaction, play/imagination, and restricted and/or repetitive behaviors published by Western Psychological Services. Used in clinical and research settings, the ADOS-2 is often referred to as the "gold standard" measure of observational assessment for autism spectrum disorder (ASD; Kanne, Randolph, & Farmer, 2008). In particular, reviewed herein is the "Toddler Module," which is designed for children 12 to 30 months of age who do not consistently use phrase speech (i.e., flexible nonechoed, three-word utterances that include a verb). The authors evaluated ADOS-2 in terms of its internal consistency, test-retest reliability, interrater reliability, content and construct validity, and predictive validity. The article rates all these positively, noting that ADOS-2 has several features that support its continued recognition as a "gold standard" assessment measure for ASD. It also finds that the inclusion of the "Toddler Module" allows for administration to a wider client population, thus enhancing the measure's effectiveness as a diagnostic tool. The authors conclude that the ADOS-2 is an effective clinical and research instrument for the ASD population. It remains a primary diagnostic tool for this population and will enhance clinical and research utility.