Purpose : Rapid population aging in South Korea is emerging as serious social problems, and interest in the health-related quality of life of the elderly is also increasing. Therefore, this study attempted to provide basic data to develop measures to improve the health-related quality of life of the elderly by identifying the impact of the elderly's dietary lifestyle on the health-related quality of life. Methods : Utilizing raw data from the Korea national health and nutrition examination survey spanning from 2011 to 2020, this study focused on individuals aged 65 and above. After excluding cases with missing data, 12,731 individuals were included in the final analysis. Various statistical methods including frequency analysis, t-tests, ANOVA, Scheffé test and hierarchical regression analysis were performed using SPSS 25.0 for windows. The statistical significance level (α) was set at .05. Results : The main results of this study were as follows. Firstly, dietary lifestyle exhibited variations depending on gender, age, education level, individual income, basic livelihood type, household type, self-rated health status, and chewing difficulty (p<.001). Secondly, there were disparities in health-related quality of life (as measured by the EQ-5D index) based on gender, age, education level, residence, individual income, basic livelihood security, self-rated health status, and chewing difficulty (p<.001). Thirdly, the EQ-5D index showed that elderly individuals' dietary lifestyle adversely impacted their health-related quality of life (F=353.74, p<.001). Conclusion : Therefore, it is necessary to prepare policies to improve the health-related quality of life by maintaining a proper diet for the elderly, and customized support and management is required taking into account the elderly's gender, age, education level, individual income, basic livelihood security, household type, self-rated health status, chewing difficulty etc.