This study was designed to evaluate family processes theoretically implicated in the onset and maintenance of adolescent self-harm. We focused on understanding parental validation and invalidation in response to their adolescent children to estimate the association between parental responses and self-harm in a high-risk group of adolescents. We also sought to determine the influence of psychotherapy on parental validation and invalidation over time during participation in a randomized clinical trial of psychotherapy designed to reduce self-harm. Teens (N = 38, Mage = 14.85, 94.1% female, 55.3% Caucasian, and 17.5% Latino) and their parents participated in three assessments over a 6-month period corresponding to pretreatment, midtreatment, and end of treatment in the trial. Results indicate a robust association between parental validation, invalidation, and adolescent self-harm. There were no significant associations observed between parental validation, invalidation, and adolescent suicidal ideation. Observed levels of parental validation and invalidation were not changed during the 6-month course of psychotherapy.