To assess the reliability and construct validity of the Personality Inventory for DSM-5 Brief Form (PID-5-BF) among adolescents, 877 Italian high school students were administered the PID-5-BF. Participants were administered also the Measure of Disordered Personality Functioning (MDPF) as a criterion measure. In the full sample, Cronbach’ s alpha values for the PID-5-BF scales ranged from.59 (Detachment) to.77 (Psychoticism); in addition, all PID-5-BF scales showed mean interitem correlation values in the.22 to.40 range. Cronbach’s alpha values for the PID-5-BF total score was.83 (mean interitem r =.16). Although 2-month test–retest reliability could be assessed only in a small (n = 42) subsample of participants, all PID-5-BF scale scores showed adequate temporal stability, as indexed by intraclass r values ranging from.78 (Negative Affectivity) to.97 (Detachment), all ps <.001. Exploratory structural equation modeling analyses provided at least moderate support for the a priori model of PID-5-BF items. Multiple regression analyses showed that PID-5-BF scales predicted a nonnegligible amount of variance in MDPF Non-Cooperativeness, adjusted R 2 =.17, p <.001, and Non-Coping scales, adjusted R 2 =.32, p <.001. Similarly, the PID-5-BF total score was a significant predictor of both MDPF Non-Coping, and Non-Cooperativeness scales. © 2015, © The Author(s) 2015.