<p>This study examined the longitudinal impact of rejecting parenting on smartphone addiction and verified the mediating effect of recreational smartphone use between rejecting parenting and smartphone addiction. The study utilized data from the Korean Children and Youth Panel Survey conducted by the National Youth Policy Institute. Using a multivariate latent growth model, the structural relationships between the rejecting parenting, smartphone addiction, entertainment-oriented smartphone use were investigated. The results showed that rejecting parenting and smartphone addiction significantly increased as the grade level progressed. The initial values and rates of change in rejecting parenting were found to have a significant positive impact on the intercept and slope of entertainment-oriented smartphone use and smartphone addiction. Entertainment-oriented smartphone use mediated the relationship between rejecting parenting and smartphone addiction. This study suggests the importance of understanding parenting attitudes and whether smartphones are used for recreational purposes in comprehending smartphone addiction during early adolescence.</p>