Background and aims: The purpose of the present study was to investigate the effects of adverse childhood experiences (ACEs) on internet gaming disorder (IGD) and the mediating effect of stress based on the Interaction of Person-Affect-Cognition-Execution (I-PACE) model. Methods: The 2017 survey data from one community addiction management center in South Korea were analyzed. A sample of 3,593 adolescents (mean age 5 13.75 years, SD 5 2.22) were recruited from 23 elementary, middle and high schools and 11 local children?s centers. The mediating effect was analyzed by the threestep analysis method. Results: Our study found that ACEs had a significant effect on the stress score (B 5 1.420, P < 0.001) and the stress scale score had a significant effect the IGD score (B 5 0.127, P < 0.001). After adjusting for the stress score in the model, ACEs had a significant effect on the IGD score (B 5 0.328, P < 0.001), and the stress score had partial mediating effects (B 5 0.1802, 95% C. I: 0.1310.239). Discussion: We found that ACEs directly affect IGD and that ACEs directly affect IGD through stress in support of the I-PACE model. In the sensitivity analysis, the mediating effect of stress in the low-risk IGD group was significant, but the mediating effect of stress in the high-risk IGD group was not significant. Prior ACEs should be considered when interviewing IGD clients. In addition, enhancing stress management skills would be beneficial to IGD clients with a history of ACEs, and actions reducing exposure to ACEs in childhood are necessary. Kulcsszavak: adverse childhood experiences; internet gaming disorder; youth; mediation; stress