Purpose: This descriptive survey-based study aimed to identify the factors associated with obese adults' quality of life (QOL) using a secondary analysis of data collected through the 8th Korea National Health and Nutrition Examination Survey (2019). Methods: In this study, factors affecting the health-related quality of life of obese adults were analyzed by categorizing them into three independent variables: general characteristics, health behaviors, and mental health characteristics. Using t-test and analysis of variance (ANOVA), an analysis was performed to determine the differences in obese adults' QOL depending on their general characteristics, health behaviors, and mental health conditions. A hierarchical regression analysis was performed to identify the factors that affect obese adults' QOL. Results: In obese adults' general characteristics, the risk factors for QOL were older age, male, lower-income level, presence of spouse, and occupation. With regard to health behaviors, the risk factors were lack of exercise. In terms of mental health conditions, the risk factors were stress and suicidal ideation. Conclusion: Obese adults' QOL was affected by age, sex, income level, absence/presence of a spouse, occupation, health behaviors (e.g., exercise), and mental health conditions (e.g., stress and suicidal ideation).