The purpose of this study was to evaluate the nutritional knowledge and dietary behaviors of middle school students according to their mother’s employment status. Of all 453 subjects, 52.1% were boys, and 67.5% of the mothers were employed. The total score of nutritional knowledge was 8.0 out of 10 for students with a non-working mom and 7.7 for those with a working mom, showing no significant difference. Among the 20 nutritional knowledge questions, correct answer rates for “lots of fruits may be eaten because of not gaining weight” (72.6% vs. 81.6%, p<0.05) and “eating raw carrots is better than eating fried ones with oil” (34.6% vs. 44.9%, p<0.05) were significantly higher in students with a working mom. The regularity of meals showed a significant difference according to the mother’s employment, indicating that responses of “very regular” (62.4% vs. 72.1%) were high among students with a non-working mom and responses of “skipping breakfast” (31.4% vs. 19.7%) were higher in students with a working mom (p<0.05). The number of snacks a day was also significantly different according to the mother’s employment, showing that 12.8% of the students with a working mom and only 3.4% of them with a non-working mom did not eat snacks at all (p<0.05). These results reveal no significant difference in middle school students’ nutritional knowledge according to their mother’s employment status; however, the students whose mother had a job were more likely to have more undesirable dietary behaviors such as irregular meals and snacking.