This study examines self-harm in a community sample of adolescents. More specifically, the study identifies the prevalence and types of self-harm, elucidates the nature and underlying function of self-harm, and evaluates the relation of psychological adjustment, sociodemographic, and health-risk variables to self-harm. Self-report questionnaires assessing self-harm, adjustment, health behaviors, suicide history, and social desirability were completed by 424 school-based adolescents. Overall, 15% of the adolescents reported engaging in self-harm behavior. Analyses revealed gender differences across behaviors and motivations. Adolescents who indicated harming themselves reported significantly increased antisocial behavior, emotional distress, anger problems, health risk behaviors, and decreased self-esteem. Results provide support for the coping or affect regulation model of self-harm. Findings suggest that self-harm is associated with maladjustment, suicide, and other health behaviors indicative of risk for negative developmental trajectories.