This study was conducted to investigate the nutrition knowledge, dietary attitudes, dietary behaviors, smartphone usagerelated dietary habits, and health-related lifestyles of higher grade students in elementary school according to risk level of smartphone overdependence. Subjects were 286 fifth and sixth grade students of elementary school in the Siheung and Ansan areas. Data were collected using self-administered questionnaires and analyzed using SPSS v. 20.0. Based on scores of S-scale (smartphone overdependence scale for adolescents), subjects who used smartphone were classified into an overdependence group (ODG, n=52) and a normal group (NG, n=234). The ODG showed a significantly longer usage time than NG on both weekdays and weekends (p<0.001). There were no significant differences in total scores of nutrition knowledge between the ODG and NG. Average total scores of dietary attitude and dietary behavior in the ODG were significantly lower than in the NG (p<0.001). There were higher risks of ODG for skipping meals (OR=8.3, 95% CI=4.027-17.099), changing eating speed (OR=4.4, 95% CI=2.209-8.822), and changing meal amount due to smartphone usage (OR=2.9 95% CI=1.233-6.623). Therefore, education programs are needed to ensure proper dietary behaviors and habits among smartphone overdependent elementary school students.