Since the diffusion of recent models of mobile phones, anyone with an internet connection can communicate continuously and search for information. This raises some questions about the possible consequences of problematic mobile phone use (PMPU) in a complex life phase such as adolescence. Therefore, we performed a psychometric analysis of the brief version of the Test of Mobile Phone Dependence (TMD) in Italy. The sample comprised 575 Italian adolescents aged 11 to 18 years. Data were collected using the TMD-brief, the Personality Inventory for the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) and the Patient-Reported Outcomes Measurement Information System (PROMIS) Sleep Disturbance Short Form. Regarding test dimensionality, the best-fit measurement model included four factors: “Abstinence”; “Abuse and interference with other activities”; “Tolerance”; and “Lack of control” (Satorra–Bentler χ2 (48) = 185.96, p < 0.01; robust root mean square error of approximation (RMSEA) = 0.079 (90% confidence interval (CI): 0.067; 0.091); robust TLI = 0.904; robust comparative fit index (CFI) = 0.930). The Italian version of the TMD-brief was found to have good reliability and psychometric properties, and a four-factorial structure. PMPU predicted significant sleep disturbances and this relationship was moderated by clinical personality traits. Findings from this study support the use of the Italian version of the TMD-brief as a screening tool to investigate PMPU in Italian adolescents.