The purpose of this secondary analysis study was to compare social networks, health-promoting behaviors, and health-related quality of life of South Korean adults, aged 65 years or older, with and without arthritis, and to identify factors that are related to health-related quality of life. The sample consisted of 103 adults with arthritis and 123 adults without arthritis. Data were analyzed using a two-way analysis of variance, X2-test, Pearson's correlation, and multiple regression analysis. All variables except age and religion showed statistically significant differences between older adults with and without arthritis. The group with arthritis reported lower scores on social networks, health-promoting behaviors, and health-related quality of life compared to the healthy group without arthritis. Analyzed using multiple regression, 43.8% of the older adults with arthritis had the factors related to health-related quality of life (F = 40.71, p < .001) including exercise (β = .43, p < .001) and living with someone (β = .32, p = .001). In the group of older adults without arthritis, 26.2% had the factors related to health-related quality of life (F = 15.44, p < .001) including exercise (β = .31, p = .001), social gatherings, and employment status. Exercise was one of the factors that showed the strongest relationship to health-related quality of life. The provision of resources that can enable an individual to engage in physical activities is warranted.