Research conducted in the aftermath of the September 11th terrorist attacks (9/11) suggests that, except for those who directly witnessed or suffered loss from the attacks, for most children the emotional impact was relatively transitory. We review this literature as well as consider other ways in which the attacks may have played a role in the development of adolescents and young adults as they came of age in the shadow of 9/11 in the United States. Specifically, we discuss the potential impact of the collective trauma of 9/11 on children's coping and emotional regulation, their sociopolitical attitudes, and their general beliefs about the world. Developmental issues and the role of parents in shaping their children's responses to 9/11 are also addressed. Researchers interested in children's social, emotional, and psychological development have much to learn about children's reactions to events like 9/11 and factors that might mitigate the negative consequences of such events on children's development.