This article uses data from the Global Appraisal of Individual Needs (GAIN) on 214 adolescents entering substance abuse treatment. The goals of the article are to validate the General Victimization Index (GVI), examine its relationship to gender and co-occurring problems, and determine its relationship to outcomes. The GVI includes 15 items on lifetime traumatic events, traumagenic factors, and current worries of victimization. The items fall along a severity dimension (alpha = .88), and evidence was generated to support the construct validity of cutoff scores for interpretation. Girls were significantly more likely than boys to have experienced a variety of victimization incidents. When used as grouping variables, gender and severity of victimization significantly interacted with measures of intake status and were significant predictors of 3-month postdischarge treatment outcomes.