Approximately 2 weeks after September 11th, adolescents from a national sample of households who were indirectly exposed to the terrorist attacks through the media completed a Web-based survey that assessed event-related acute stress symptoms. One year later, these adolescents (N = 142) and a randomly selected parent from their household completed a second survey. On average, adolescents reported mild to moderate acute stress symptoms shortly after the attacks and few trauma-related symptoms, low psychological distress and functional impairment, and moderate levels of positive affect 1 year later. After adjusting for acute stress symptoms reported after the attacks, greater parent-adolescent conflict was positively associated with adolescents' trauma symptoms, distress, and functional impairment at 1 year. Higher levels of adolescent positive affect at 1 year were associated with greater parental positive affect, greater parental support, and higher levels of parenting self-efficacy. Parents may play an important role in adolescents' responses to stressful national events. (Contains 3 tables and 2 figures.)