The aim of this study was to identify the prevalence of media addiction and its associated factors in elementary school children based on the problem behavior theory. This cross-sectional study was a secondary data analysis using national data from the 10th Panel Study on Korean Children 2017, which included 1,078 families of third-grade students (8-9 years of age). Descriptive statistics were used to examine the prevalence of media addiction, and logistic regression analysis was conducted to identify factors associated with media addiction. Prevalence of media addiction was 22.91% in this sample. Media addiction was significantly associated with general characteristics (gender, education level of mother, and time spent without parents), socialization (media use time), factors in the personal system (happiness), and factors in the perceived-environment system (parenting style). More comprehensive, tailored education may prevent elementary school children's media addiction. In addition, parents should participate in media addiction education with their children.