In this secondary analysis of a previously conducted systematic review, we analyze social validity assessments in intervention research for transition-age autistic youth. Social validity is concerned with the acceptability of the intervention goals, the acceptability and feasibility of the intervention procedures, and the perceived importance of the intervention outcomes. We found that although just over half of intervention studies assessed some aspect of social validity, only 43% of those studies examined all three dimensions. There were several shortcomings of the social validation procedures, including a lack of psychometric validation for quantitatively scored questionnaires and a failure to describe qualitative procedures for analyzing open-ended questions. These shortcomings likely explain why interpretations of social validity assessments were nearly universally positive.