Background: Internet Gaming Disorder (IGD) is recognized as a significant health issue in adolescents. However, the cross-national comparison and validation remain underrepresented in the literature. Thus, this study aimed to evaluate the symptom prevalence, dimensionality, and measurement invariance of the nine-item Internet Gaming Disorder Scale (IGDS) with data from the 2021-22 Health Behaviour in School-aged Children survey. Methods: Representative samples of adolescents aged 11-15 from 12 European regions (N 5 44,126) were used. The IGDS was examined using network analyses and factor models with dynamic cut-offs. Results: Gaming intensity was more related to IGDS score than gaming frequency. Non-gaming boys at the time of measurement reported similar IGDS scores as daily gamers. All symptoms were more common in boys; Escapism and Preoccupation were the most common symptoms overall. A unidimensional structure for the IGDS across both genders and all regions was indicated. Only configural invariance was observed across genders, with notable higher roles for ?Problems" and "Preoccupation" in boys, suggesting problematic direct gender comparisons. Measurement invariance suggested three relatively homogenous region groups, showing varying levels of invariance, and some groups achieving scalar invariance. Consequently, cross-regional comparisons should be approached with caution. Conclusions: The findings suggest large differences between boys and girls, moderate differences between age groups, and relatively high differences among regions.  Kulcsszavak: Internet Gaming Disorder, prevalence, psychometrics, network analysis, measurement invariance, HBSC