This study was performed to investigate the nutrition knowledge, dietary attitudes, and dietary behaviors among high school students by gender. The subjects were 275 students (127 male, 148 female) in Incheon metropolitan area. Selfadministered questionnaires consisted of general characteristics and anthropometric data, nutrition knowledge, dietary attitudes, and dietary behaviors. The average score of nutrition knowledge was significantly higher in female subjects (9.4) compared to male subjects (8.2) (p<0.01). Male subjects had a higher score for dietary attitudes than female subjects (p<0.001). Frequency of meals was significantly higher in male subjects compared to female subjects (p<0.05). Duration of meal time in male subjects was significantly higher (‘5-10 minutes’) compared to female subjects (p<0.001). Unbalanced diet was significantly higher in female subjects (66.3%) compared to male subjects (48.9%) (p<0.01). Male subjects showed significantly higher consumption frequency of ‘dairy’ (p<0.001) and ‘beans’ (p<0.001) compared to female subjects. For snack consumption, male subjects showed higher consumption frequency of ‘nuts’ (p<0.001), ‘soda’ (p<0.05), ‘fast foods’ (p<0.001), and ‘ramyeon’ (p<0.01), but lower consumption frequency of ‘biscuits and bakery’ (p<0.01) compared to female subjects. Therefore, it is necessary to develop a systemic nutrition education program for high school students by gender.