The purpose of this study was to identify factors influencing health-related quality of life (HRQoL) of overweight and obese children in Korea. This study employed a cross-sectional descriptive study design. A total of 132 overweight and obese children participated in the study. Anthropometric measurements included body mass index, percent body fat, and waist--hip ratio. The instruments included lifestyle patterns, psychosocial characteristics (stress, self-esteem, and depression), and HRQoL. The study found that significant predictors of HRQoL included self-esteem, depression, and physical stress; these variables accounted for 58.7% of the variance (p < 0.05), while children with low monthly household income had significantly lower HRQoL, compared with that of their counterparts (p < 0.05). HRQoL has multiple dimensions, thus, in addition to lifestyle change, health programs for overweight and obese children should focus on psychological health, and consider social and environmental factors as well.