Dysfunctional trauma-related cognitions are associated with posttraumatic stress disorder (PTSD). The psychometric properties of the German version of the Child Post-Traumatic Cognitions Inventory (CPTCI-GER) were assessed in a sample of 223 children and adolescents (7–16 years) with a history of different traumatic events. Confirmatory factor analyses supported the original two-factor structure—permanent and disturbing change (CPTCI-PC) and fragile person in a scary world (CPTCI-SW). The total scale and both subscales showed good internal consistency. Participants with PTSD had significantly more dysfunctional trauma-related cognitions than those without PTSD. Dysfunctional posttraumatic cognitions correlated significantly with posttraumatic stress symptoms (PTSS; r = .62), depression (r = .71), and anxiety (r = .67). The CPTCI-GER has good psychometric properties and may facilitate evaluation of treatments and further research on the function of trauma-related cognitions in children and adolescents. (Partial) correlations provide empirical support for the combined DSM-5 symptom cluster negative alterations in cognitions and mood.