The increasing popularity and accessibility of online games among schoolchildren, particularly through smartphones, has raised concerns about potential addiction, which may adversely affect their social-emotional development. The factors contributing to this issue include insufficient parental supervision and a lack of awareness. This study aimed to examine the relationship between online game addiction and social-emotional development in children. This study employed an analytical observational design with a cross-sectional approach. The sample consisted of 171 respondents selected through a proportionate stratified random sampling method. The study utilized the Gaming Addiction Scale (GAS) and the Strengths and Difficulties Questionnaire (SDQ) to assess the levels of online game addiction and social-emotional development, respectively. Spearman's rho correlation test was applied for data analysis. Most respondents (52.6%) were categorized as having moderate online game addiction, whereas 91.2% exhibited abnormal social-emotional development. A statistically significant relationship was found between online game addiction and social-emotional development in school-age children, with a p-value of 0.001 and a moderate correlation coefficient of 0.310. Online game addiction significantly affects the social-emotional development of children. It is crucial to monitor children's game usage and its potential impacts. Prevention efforts should focus on educational interventions, support parents and schools.