Psychological trauma and the human response to trauma have been characterized as one of the most important threats to public health. Developmental trauma, referring to traumatic events experienced during childhood and/or adolescence, is of particular concern given the potential biological, neurological, psychological, and relational impact of trauma on the developing child, with possible consequences lasting a lifetime. Youth may deal with developmental trauma by utilizing disordered eating behaviors like loss of control eating in efforts to cope with distress; loss of control eating can, in turn, cause excess weight gain. Adolescence is a particularly salient time for the initiation and maintenance of disordered eating, but it is unclear to what extent developmental trauma is associated with loss of control eating and excess weight in adolescence. Further, it is unknown what role developmental trauma has on affect and attachment, two developmental domains presumed to be affected by trauma, and how affect and attachment are associated with loss of control eating and excess weight gain in adolescence. This dissertation project utilized secondary data from a sample of adolescents at risk for excess weight gain, by having above-average body mass index (BMI >70 percentile for age and sex) or having a family history of overweight or obesity, to evaluate two aims. The first aim investigated associations between developmental trauma and disordered eating and developmental trauma and excess body weight, measured as BMI standard score, in adolescence. The second aim explored negative affect, measured as symptoms of depression and symptoms of anxiety, and attachment, measured as emotional support, as mediators of the associations of developmental trauma with disordered eating and BMI standard score. Approximately 58% of the sample endorsed at least one traumatic event. Developmental trauma count was associated with greater depressive and anxiety symptoms and lower BMI standard score, but it was not significantly associated with global disordered eating or loss of control eating. An indirect effect of developmental trauma on global disordered eating via depressive symptoms was observed. Symptoms of anxiety and emotional support did not mediate the associations of developmental trauma with disordered eating or BMI standard score. Results highlight the unique role of depressive symptoms in the relationship of developmental trauma to disordered eating. If replicated, particularly with a longitudinal design, findings have the potential to inform prevention and intervention efforts for a particularly vulnerable population: youth who have experienced trauma and may be at risk for or are experiencing disordered eating and excess body weight.