Objectives: This study examined the effects of parenting behaviors and children's happiness on children's media device addiction. Methods: The data were drawn from the tenth wave of the Panel Study on Korean Children. A total of 1,263 children and their parents answered questionnaires on the research variables. Data were analyzed using structural equation modeling. Results: First, maternal parenting behaviors had a direct effect on children's media device addiction, that is, children whose mothers displayed more positive parenting behaviors showed less media device addiction. Second, maternal parenting behaviors had an indirect effect on children's media device addiction through happiness. In other words, when mothers exhibited more positive parenting behaviors, their children tended to be happier, which, in turn, led to less media device addiction. However, paternal parenting behaviors did not have any direct or indirect effects on children's media device addiction. Conclusion: This study confirmed that positive maternal parenting behaviors and children's happiness are protective factors for children's media device addiction. In addition, these findings contribute to a better understanding of the mechanisms linking parenting behaviors to children's media device addiction.