Objective: Problematic internet gaming in adolescents is associated with various negative outcomes, such as low self-esteem, depression, anxiety, and attention problems. We hypothesized that game coding education, by improving adolescents’ self-esteem, would be more effective than game literacy education in mitigating problematic internet gaming. Methods: A total of 126 adolescents who voluntarily applied for the game coding education and game literacy education program of the “Visiting Game Class” project operated by the Game Cultural Foundation participated in this study. We collected data on demographics, gaming patterns, and psychological status, including positive or negative perceptions of online games, depression, and anxiety. We designated those with scores higher than 40 on Young’s Internet Addiction Scale as the “problematic internet gaming” group. Results: Only game coding education was significantly effective in decreasing internet use, lowering depressive symptoms, and improving self-esteem. In the hierarchical logistic regression analysis, more frequent education time, coding education, stronger negative perceptions of gaming, and high self-esteem predicted decreased internet gaming among participants exhibiting problematic internet gameplay. Conclusion Game coding education effectively mitigates problematic gaming by improving adolescents’ self-esteem. Thus, it may be beneficial to increase education time and devise game education programs tailored to adolescents’ psychological status.