As the number of children engaging in problem behaviors grows, teachers increasingly report feeling unprepared to effectively meet students' mental health needs. Social-emotional learning (SEL) should be a prominent goal of school programs because social competence prevents school failure. This commentary reviews the challenges associated with implementing and researching school-based SEL programs, examines the current state of the evidence-based literature on SEL, and comments on the companion articles that appear in this Journal of Educational and Psychological Consultation special topic section.