The 15-item Generalized Problematic Internet Use Scale 2 (GPIUS2) is one of the few theory-driven instruments to measure problematic Internet use (PIU). Since PIU has emerged in several cultural contexts, it seems relevant to evaluate the psychometric properties of the scale across various cultures. The aim of the present study was to test the psychometric properties (i.e., dimensionality, reliability, and validity) of the Italian version of the GPIUS2. The sample consisted of 371 participants (128 males and 243 females), and their age ranged from 14 to 33 years (M=18.07 years, SD=5.58). The GPIUS2 and the Internet Addiction Test (IAT) were administered individually in both high school and college classes. With regard to scale dimensionality, the best-fit measurement model includes four first-order factors: preference for online social interaction, mood regulation, deficient self-regulation, and negative outcomes (Satorra-Bentler scaled chi-square [S-Bχ(2)]/df=2.27; comparative fit index [CFI]=0.94; Tucker-Lewis index [TLI]=0.93; root mean square error of approximation [RMSEA]=0.05). With regard to reliability, internal-consistency Cronbach's alpha ranged from 0.78 to 0.89. Convergent validity is demonstrated with significant correlations between GPIUS2 (total score and all the subscale scores) and IAT score. Results showed that GPIUS2 scores significantly discriminated between high school and undergraduate students. The overall findings of the present study provide evidence that the Italian version of the GPIUS2 appears to be an adequate measure of generalized PIU cognitions, behaviors, and outcomes. Suggestions for further research are provided.