With the introduction of the ICD-11 diagnostic manual, the need for developing and validating new assessment instruments has become urgent. The International Trauma Questionnaire-Child and Adolescent version(ITQ-CA) assesses posttraumatic stress disorder (PTSD) and complex PTSD (CPTSD) based on the ICD-11 diagnostic definition. This study examines the psychometric properties of the Danish version of the ITQ-CA in a non-clinical sample of 226 adolescents. Hierarchical multiple regression analyses were performed to study the effects of gender, age, trauma exposure, family dysfunction, and SDQ variables on PTSD and Disturbances in Self-Organization (DSO). Results showed that 16 participants (7%) met the ITQ-CA criteria for CPTSD and 11 (5.7%) for PTSD. The full model of gender, age, family dysfunction, trauma exposure, and SDQ variables was found to predict PTSD and DSO. The present study supports the validity of the Danish version of the ITQ-CA and represents an important step of establishing and applying validated tools for assessing PTSD and CPTSD in children and adolescents. The results also underscore the need for a broader trauma definition. Future research should examine the sensitivity of the ITQ-CA.