Several changes have been made to the diagnostic criteria for posttraumatic stress disorder (PTSD) in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders. The present study attempts to establish the validity and reliability of the new PTSD Checklist for the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (PCL-5). A group of 597 Malaysian adolescents (Mage = 16.9, SD = 1.30) completed the PCL-5, Harvard Trauma Questionnaire, and Patient Health Questionnaire for depression (PHQ-9). The results showed the PCL-5 has good internal consistency (α = .91), test–retest reliability (r = .61), and concurrent, convergent, and discriminant validity with the Harvard Trauma Questionnaire (r = .69) and the Patient Health Questionnaire for depression (r = .56). Results from the receiver operating characteristic curve and kappa coefficient analysis suggest that a PCL-5 cutoff score of 33 is feasible for use among Malaysian adolescents with 72% sensitivity and 92% specificity. Thus, the PCL-5 appears psychometrically sound, and a cutoff of 33 is recommended for PTSD screening among the Malaysian adolescent population.