This study examined the influence of the nutrient intake status, dietary habit, and academic stress of elementary school children on their academic achievement. Two-hundred and twenty-four fifth-graders in Bucheon-si, Gyeonggido were surveyed. The study included the 24 hr-recall, anthropometric measurement, assessment of stress level and academic achievement. The subjects were normal in height, weight and Rohrer index, but higher percentage of underweight was seen in girls and vice versa in boys. The overall nutrient intake and dietary habits were fairly good, but Ca and folate intake was less than 75% KDRIs and dietary habits of boys were inferior. Academic stress level of all the subjects was not high. In terms of academic performance and its relations with nutrient intake, the more the amount of nutrient intake, the higher the academic performance. Especially, it was true for the energy, protein, phosphorus, potassium, zinc, polyunsaturated fatty acids, and n-6 fatty acid intakes (p < 0.05). The overall academic performance was higher for those who eating-out less frequently. Children with higher comprehensive dietary habit scores have shown better academic performance (p < 0.05). Less stress implied to those shown higher academic achievement while those with relatively poor academic performance showed high stress level since their grade did not improve as much as they anticipated. In conclusion, the academic achievement was higher for those who have a better nutritional status, better dietary habits, and lower stress levels. Therefore, it is critical for nutritionists, parents, and teachers to improve the nutritional status and dietary habits as well as to help them manage their stress levels, which will eventually contribute to an enhanced academic performance.