Social development was maturity in social relationships that was influenced by the process of parental treatment or guidance of children in various aspects of social life, and the norms of community life in social relationships. The purpose of the study was to analyze the effect of the use of Free Fire online games on the social development of children aged 6-12 years. The type of research used was pre-experimental one group pretest posttest design. The population of this study was children aged 6-12 years in Lebak Hamlet, Lebaksono Village, Pungging District, Mojokerto Regency, amounting to 50 respondents. The sampling technique used purposive sampling. Sample size was 20 respondents. The research instrument used a questionnaire. Data analysis used Wilcoxon Signed Rank test. The results siuggested that the social development of the respondents before playing the Free Fire Game was mostly good, as many as 13 respondents (65%), while the social development of the respondents after playing the Free Fire Game was half in the bad category, as many as 10 respondents (50%). The results of the Wilcoxon Signed Rank test suggested that p value = 0.083 with a Z value of 1.732 with a negative relationship direction so that there was no influence of free fire games on the social development of children 6-12 years old in Lebak Hamlet, Lebaksono Village, Pungging District, Mojokerto Regency. One solution for online game addiction could be handled in several ways, for example reducing time to play games, limiting time playing online games, increasing other positive activities or activities such as exercising.