The study found that CU traits were associated with a greater likelihood of the adolescent offending in groups and being in a gang. Importantly, both associations remained significant after controlling for the adolescent's age, level of intelligence, race and ethnicity, and level of impulse control. The association of CU traits with gang membership also remained significant after controlling for the adolescent's history of delinquent behavior. Further, CU traits were associated with several measures of taking a leadership role in group crimes. CU traits were also associated with greater levels of planning in the group offense for which the adolescent was arrested, although this was moderated by the adolescent's race and was not found in Black youth. These results highlight the importance of CU traits for understanding the group process involved in delinquent acts committed by adolescents. They also underscore the importance of enhancing the effectiveness of treatments for these traits in order to reduce juvenile delinquency. This analysis was conducted in an ethnically and racially diverse sample (N = 1,216) of justice-involved adolescents (ages 13 to 17) from three different sites. (Publisher abstract modified)