Background and aims: Considering the growing number of gamers worldwide and increasing public concerns regarding the negative consequences of problematic gaming, the aim of the present systematic review was to provide a comprehensive overview of internet gaming disorder (IGD) by identifying all empirical studies on biological, psychological, and social factors of IGD.Methods: A systematic literature search was conducted through PsycINFO, PubMed, RISS, and KISS, and papers published up to August 2021 were included. Studies were screened based on the IGD diagnostic tool usage, and only five scales with well-established psychometric properties were included. A total of 88 studies were included in the synthesis, and the results were classified into three groups.Results: Biological factors (n=8) included reward, self-concept, brain structure, and functional connectivity. Psychological factors (n=57) included psychiatric symptoms, psychological health, emotion regulation, personality traits, and other dimensions. Social factors (n=29) included family, social interaction, culture, school, and social support.Discussion: Impaired self-concept, associations with psychiatric symptoms, and poor academic performance were consistently found in IGD. On the other hand, inconsistent findings were observed with regards to the remaining dimensions, including reward activities, impulsivity, social interaction, and family-related factors. However, it is premature to make conclusions on some dimensions with lack of study results.Conclusions: More longitudinal and neurobiological studies, consensus on a diagnostic tool with well-defined psychometric properties, and an in-depth understanding of gaming-related factors should be established for IGD to be considered a clinically relevant syndrome and to gain greater legitimacy in the field of behavioral addiction.