Purpose: The purpose of this descriptive study was to identify gender differences in predictors on dietary self-efficacy in fifth and sixth grade elementary school children. Methods: The data were collected by a questionnaire given to the 408 children between June 7 to June 17, 2011. Descriptive statistics, t-test, ANOVA, Pearson’s correlation coefficients and stepwise multiple regression were used to analyze the data. Results: There were gender differences in dietary self-efficacy, exercise self-efficacy, dietary practice and depression. Dietary self-efficacy had a significant positive correlation with exercise self-efficacy and dietary practice and negative correlation with depression for both girls and boys. The predictors of dietary self-efficacy for boy were exercise self-efficacy and dietary practice, these factors explained 37.1% of the total variance. In girls, exercise self-efficacy and dietary practice were significant predictors and explained 38.7% of dietary self-efficacy. Conclusion: Based on the finding of this study, it is needed to develop a nursing intervention for dietary self-efficacy in elementary school children including to promote exercise self-efficacy and dietary practice.