--- - |2+ Abstract Objective Research investigating the social context of adolescent nonsuicidal self‐injury (NSSI) has been limited. We therefore examined social characteristics of NSSI, such as knowledge of friends’ NSSI and the role friends play in continuing NSSI, and their relationships to other known NSSI correlates, such as suicidality. Method We assessed NSSI characteristics, including social features, in a community sample of 89 self‐injuring adolescents. We also assessed psychosocial correlates of NSSI, including impulsivity, self‐concept, and psychiatric symptoms. Results Knowledge of friends’ NSSI was relatively common among self‐injurers. In addition, knowledge of friends’ NSSI was associated with use of more NSSI methods, cutting behaviors, and suicidal ideation, but not with other NSSI correlates. However, teaching or encouragement of NSSI by friends was rare. Conclusions Knowledge of friends’ NSSI may serve as marker of increased severity among adolescent self‐injurers. These findings have implications for identifying and intervening with high‐risk self‐injuring youth. - Journal of Clinical Psychology, EarlyView.