This literature review evaluated early behavioral intervention studies of Autism Spectrum disorder (ASD) based on their participant exclusion criteria. The studies included were found through searching PsycINFO and PubMed databases, and discussed behavioral interventions for children up to 5 years of age with ASD and utilized a group research design. Studies reviewed were categorized into three groups: Restrictive exclusion criteria, loosely defined exclusion criteria, and exclusion criteria not defined. Results indicated that studies that used restrictive exclusion criteria demonstrated greater differences in terms of outcomes between experimental and control groups in comparison to studies that used loosely defined exclusion criteria and/or did not define any exclusion criteria. We discussed implications for the generalizability of the studies’ outcomes in relationship to exclusion criteria.