This study aimed to assess the association between the weight status and dietary behavior of preschool children. The survey included 412 preschool children aged 2-5 years in 31 childcare facilities in Gwangju. General characteristics of children and their mothers, weight, height, feeding type, complementary feeding, food allergy, and dietary behavior of children based on the Nutrition Quotient for preschoolers (NQ-P) questionnaire were considered. Children were classified into 4 groups by weight status; underweight, normal, overweight, and obese, based on the 2017 Korean National Growth Charts. The percentage of children in the respective groups was 5.3, 70.9, 10.7, 13.1%. Weight status was not related to breast feeding duration nor the starting time of complementary feeding. The NQ-P scores of underweight, normal, overweight, and obese groups were 55.4, 60.0, 60.8, 60.0. Among the three factors covered by the NQ-P, ‘balance’ and ‘environment’ scores of the underweight group were lower than that of other groups. Underweight children consumed beans, fish, and white milk less frequently. The ‘moderation’ scores of the overweight/obese group were lower than those of the normal or obese groups. Obese children more frequently ate processed meat and fast foods. Proper nutrition education is thus needed for not only obese children but also underweight children based on their age, along with their parents, and caregivers.