Post-traumatic stress disorder (PTSD) is a disruptive condition associated with great suffering. Fortunately, effective treatments are available. Assessment of children and adolescents with symptoms of PTSD is done within the child and adolescent mental health services. Adults are assessed in primary healthcare settings. In complex conditions with psychiatric comorbidity, assessment is conducted in specialist psychiatric services. Trauma-focused psychotherapy is the treatment of choice for both children and adults. Trauma-focused psychotherapy is also recommended for treating complex PTSD, despite a weaker evidence base. PTSD-specific treatment should normally be offered even in the presence of psychiatric comorbidities. Treatment of children and adolescents with PTSD and CPTSD is provided by child and adolescent mental health services. Adults can receive treatment both in primary and secondary healthcare settings, depending on symptomatology and comorbidities.