This article reports on mother-child conflict as an outcome and moderator of Interpersonal Psychotherapy-Adolescent Skills Training (IPT-AST), a preventive intervention for depression. Forty-one adolescents (average age = 13.37, SD = 1.19) with elevated depression symptoms were randomized to receive IPT-AST or school counseling (SC). Adolescents in IPT-AST showed significantly greater reductions in mother-child conflict. Baseline mother-child conflict moderated the programs' effects on depression symptoms. Adolescents in IPT-AST who had high baseline conflict showed significantly greater decreases in depression symptoms than adolescents in SC who had high conflict. Among those adolescents with low baseline conflict, the difference between the two interventions was not significant.