This study investigated the gender differences in smartphone addiction (SA) behaviors associated with parent-child bonding, parent-child communication, and parental mediation among Korean elementary school students aged 11-13 years. A sample of 224 smartphone users (112 boys and 112 girls) was surveyed in a cross-sectional study. Descriptive statistics and multiple regression analysis were conducted to investigate the predictors of SA behaviors based on gender differences using SPSS Win 23.0 software. Of the participants, 14.3% (15.18% boys and 13.39% girls) were in the SA behaviors risk group, and the prevalence of SA behaviors was not significantly different between gender groups. In multiple stepwise regression analysis, less active safety mediation; longer duration of smartphone use; more use of smartphones for games, videos, or music; and less restrictive mediation were linked to higher SA behaviors in boys, and these indicators accounted for 22.1% of the variance in SA behaviors. Longer duration of smartphone use, less active use mediation, worse parent-child communication, and more use of smartphones for text, chatting, or social network sites were linked to higher SA behaviors in girls, and these indicators accounted for 38.2% of the variance in SA behaviors. The study provides insights into SA behaviors and predictors of SA behaviors among children based on gender differences. Development of SA behavior prevention programs is needed, not only for children but also to teach parents to use active safety mediation and restrictive mediation for boys and better communication and active use mediation for girls.