This review is aimed at identifying assessment instruments used to measure treatment outcomes in children with autism spectrum disorder who received early and intensive behavioral interventions. Forty three articles were included and appraised using the Council for Exceptional Children's Standards for Evidence Based Practice quality index rater. Ninety-two outcome measures were discovered. Measures of adaptive functioning (91%), intellectual functioning (86%), and core symptoms (67%) of autism were represented with the highest frequencies. Measures of challenging behavior and parent or caregiver wellbeing were reported at 30% and 14% respectively. Reliability and validity of each measure were determined by recently published psychometric data. The utility of outcome measures in clinical practice is discussed.