Research clearly shows that heterogeneity exists in the etiology, associated characteristics, and outcomes of social withdrawal/isolation. While individual level characteristics are thought to contribute to withdrawal and isolation, research suggests that peer relations may play an important role in the extent to which social withdrawal/isolation are maintained over time. The purpose of the present study was to identify subtypes of withdrawal and to determine which characteristics led to persistent isolation across third grade. Using a social cognitive mapping procedure, 146 children in second grade were identified as having no mutual friendships and as not belonging to any peer group in their classrooms. Using peer nominations for prosocial, internalizing, and externalizing characteristics, three subtypes were identified that correspond to those previously identified in the extant literature on withdrawal and isolation: an "Active Isolates" class, a "Passive-Anxious" class, and a "Low Salience" class. Aggressive and internalizing behaviors predicted peer victimization, which in turn was the only significant predictor of persistence in isolation over time. Gender differences were found in the relations of specific behavioral characteristics to persistent isolation in third grade. Observed relationships between behavioral characteristics, peer victimization, and subsequent isolation also differed between previously isolated and non-isolated children. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]