This study examined the association between traumatic exposure and mental health outcomes in sheltered homeless children. Also investigated was the moderating role of perceived social support in the pathway between traumatic exposure and emotional distress. Trauma exposure was conceptualized in two ways: first through lifetime exposures to abuse, neglect, negative peers, community and interpersonal violence, and the loss of significant attachment figures, and; second through highly stressful events that occur s pecifically in the context of homelessness. Mental health outcomes included symptoms of depression, anxiety, anger, aggression and posttraumatic stress. Perceived social support was measured through inventories of relationships with mothers, fathers, siblings and best friends. The sample consisted of 81 children between the ages of 8-16 and one of their parents. Hierarchical multiple regression analyses found that lifetime trauma exposure and homeless specific complex stress independently accounted for a significant amount of the variance in symptoms of depression, anxiety, aggression, and posttraumatic stress. Lifetime trauma alone accounted for the variance in anger and anxiety related symptomatology. Perceived social support was found to have no influence on mental health morbidity. The study consisted of a novel approach to understanding the psychological experiences of sheltered homeless children. These findings inform the design of clinical interventions for this vulnerable population of children and may have important public policy implications.