Background and Objectives: This study examined the association between active aging and health-related quality of life (HRQoL) in older Korean adults. Furthermore, it examined how socioeconomic factors were related to active aging and HRQoL. Methods: Data were analyzed using the 8th Korea National Health and Nutrition Examination Survey (KNHANES). This study used the Health-Related Quality of Life Instrument with Eight Items (HINT-8), a Korean-specific HRQoL instrument. Multivariable regression analyses were conducted to estimate the associations of overall active aging and its health, participation, and security domains with HRQoL. Results: The health domain showed the largest coefficient, and the security domain was also significantly associated with HRQoL. The participation domain showed a relatively limited and statistically non-significant association, which may partly reflect measurement constraints in the operationalization of participation. Older adults with lower educational levels and those residing in rural areas had lower levels of both active aging and HRQoL. Conclusions: Active aging was positively associated with HRQoL among older Korean adults. These findings highlight health as the domain most strongly associated with HRQoL and identify security as an additional relevant domain, while participation-related findings should be interpreted cautiously given the limited operationalization of participation and its statistically non-significant association. However, longitudinal or intervention studies are needed to examine temporal and causal relationships between active aging and HRQoL.