This study used an item response theory (IRT) model and a large adolescent sample of justice involved youth (N = 1,007, 38% female) to examine the item functioning of the Psychopathy Checklist-Youth Version (PCL: YV). Items that were most discriminating (or most sensitive to changes) of the latent trait (thought to be psychopathy) among adolescents included "glibness/superficial charm," "lack of remorse," and "need for stimulation," whereas items that were least discriminating included "pathological lying," "failure to accept responsibility," and "lacks goals." The items "impulsivity" and "irresponsibility" were the most likely to be rated high among adolescents, whereas "parasitic lifestyle," and "glibness/superficial charm" were the most likely to be rated low. Evidence of differential item functioning (DIF) on 4 of the 13 items was found between boys and girls. "Failure to accept responsibility" and "impulsivity" were endorsed more frequently to describe adolescent girls than boys at similar levels of the latent trait, and vice versa for "grandiose sense of self-worth" and "lacks goals." The DIF findings suggest that 4 PCL: YV items function differently between boys and girls.