We reviewed the demographic reporting practices and diversity of participants in published randomized controlled trial studies of group-based social skills interventions (GSSIs) for individuals with autism spectrum disorder (ASD). A total of 17 studies met inclusionary criteria. Results of this review suggest that the majority of published RCTs reported on participant gender and race/ethnicity, with fewer studies including details on household income and caregiver education. Study samples generally lacked diversity, with an overrepresentation of participants who were male, White, and from upper-middle class backgrounds. Additionally, we found that nearly all GSSI studies focused on participants with average or high IQs, or were specifically classified as having a higher functioning sub-diagnosis within ASD. Implications and future directions for research are discussed.