Background and aims: The study aims to thoroughly understand the causal and precedent modifiable risk or protective factors for Internet Gaming Disorder (IGD), a newly defined and prevalent mental disorder. Methods: We performed a systematic review on quality-designed longitudinal studies based on five online databases: MEDLINE, PsycINFO, Embase, PubMed, and Web of Science. Studies were included in the meta-analysis if they addressed IGD, adopted longitudinal, prospective, or cohort study designs, presented modifiable factors of IGD, and reported the effect sizes for correlations. Pooled Pearson?s correlations were calculated using the random effects model. Results: Thirty-nine studies with 37,042 subjects were included. We identified 34 modifiable factors, including 23 intrapersonal factors (e.g., gaming time, loneliness, etc.), 10 interpersonal factors (e.g., peer relationship, social support, etc.), and 1 environmental factor (i.e., school engagement). Age, the male ratio, study region, and study years were significant moderators. Discussion and conclusions: Intrapersonal factors were stronger predictors than interpersonal and environmental factors. It may imply that individual-based theories are more powerful to explain the development of IGD. Longitudinal research on the environmental factors of IGD was lacking; more studies are warranted. The identified modifiable factors would help to guide effective interventions for IGD reduction and prevention.  Kulcsszavak: meta-analysis, modifiable factors, internet gaming disorder, behavioural addiction, longitudinal studies