BackgroundPrevious studies have indicated that social connectedness can serve as a protective buffer against negative outcomes associated with online victimization. However, the role of social connectedness between Internet gaming disorder and somatic symptoms is still unclear. This study aims to examine the mediating effect of social connectedness on the association between Internet gaming disorder and somatic symptoms.MethodsA cross-sectional design was utilized, using questionnaires for data collection and multi-stage stratified cluster sampling. The general demographic questionnaire, Nine-Item Internet Gaming Disorder Scale–Short Form, Social Connectedness Scale-Revised and Patient Health Questionnaire Physical Symptoms were used to collect data. We adopted Pearson’s correlation analysis and the PROCESS Macro Model in regression analysis to explore the relationships among Internet gaming disorder, social connectedness and somatic symptoms.ResultsInternet gaming disorder was positively correlated with somatic symptoms (r = 0.20, P < 0.001), while network (r=-0.08, P < 0.001) and real-life social connectedness (r=-0.31, P < 0.001) negatively affected somatic symptoms. The network social connectedness and the real-life social connectedness played a chain mediating role in the development of Internet gaming disorder to somatic symptoms [95%CI: 0.073, 0.088], explaining 45.25% of the total effect value. The difference of real-life social connectedness and network social connectedness played a partial mediating role between Internet gaming disorder and somatic symptoms [95% CI:0.050, 0.062], accounting for 31.28% of the total effect value.ConclusionsReal-life social connectedness, network social connectedness, and their disparity all mediated the relationship between Internet gaming disorder and somatic symptoms. Real-life social connectedness acted as a protective factor, while network social connectedness served as a risk factor. Encouraging offline activities and guiding teenagers to use the internet responsibly may help prevent and reduce physical symptoms linked to Internet gaming disorder.