The purpose of this content analysis was to examine the use of theory in school-counselor-led interventions. Specifically, we examined intervention characteristics, evaluation design, and use of theory in school-counselor-led intervention studies that were published by the American Counseling Association, the American School Counselor Association (ASCA), and in other school-counseling-related journals from 2003 to 2022. Drawing from 45 published articles, results indicated that few school counseling articles explicitly included ASCA Mindsets & Behaviors (ASCA, 2021) or integrated formal counseling theory to inform student outcomes.