The Diagnostic Interview Schedule for Children (DISC-2.1C), including the posttraumatic stress disorder (PTSD) module, was administered to 109 American Indian adolescents from a Northern Plains reservation. In response to the DISC's open-ended probes, 61% of respondents reported at least one traumatic event. Despite high rates of trauma and substantial numbers of subsyndromal PTSD symptoms, the prevalence rate of diagnosable PTSD was found to be only 3%. The reporting of traumatic events was associated with increased prevalence of behavioral disorders and substance abuse or dependence diagnoses. There was, however, no significant difference in academic performance (grade point average or scholastic aptitude test scores) between those who reported traumatic events, or PTSD symptoms, and those who did not.