Background: Dysfunctional trauma-related cognitions play an important role in the aftermath of a traumatic event. Children and adolescents, who think that the experienced trauma has a permanent and disturbing impact on their actual life and their future, feel threatened. Study results show that dysfunctional posttraumatic cognitions correlate highly with posttraumatic stress symptoms (PTSS), depression, and anxiety. In addition, children and adolescents with a posttraumatic stress disorder (PTSD) have significantly more dysfunctional trauma-related cognitions than those without PTSD. Especially for children and adolescents it is important to consider interacting developmental and environmental factors. A developmental approach, nevertheless, has not been investigated yet.