The goals of the current study were to examine the prevalence of secondary stressors related to Hurricane Katrina and to determine their impact on posttraumatic stress disorder (PTSD) symptoms among a sample of high school students. In addition, the moderating role of problem substance use was examined to determine whether it increased the risk of PTSD symptoms in the face of secondary stressors. A total of 271 ethnically and socioeconomically diverse adolescents completed an anonymous survey. Results indicated that problem substance use potentiated the positive relation between secondary stressors and PTSD symptoms, specifically symptoms of re-experiencing. The findings highlight the need for school-based assessment of and interventions for the long-term psychological effects of disasters. (Contains 1 figure and 3 tables.)