Purpose: The purpose of this study was to identify the mediating effect of health behavior between meaning in life and happiness related to aging among community-dwelling older adults during the COVID-19.Methods: The subjects of this study were 140 older adults in D city. Data were collected from July 21 to August 23 in 2020 using structured questionnaires and analyzed with IBM SPSS 25.0 program. Data were analyzed via independent t-test, one-way ANOVA, Pearson's correlation coefficients, and regression following the Baron and Kenny method and Sobel test for identifying mediating effect.Results: Happiness related to aging was positively correlated with meaning in life (r=.33, <i>p</i><.001) and health behavior (r=.50, <i>p</i><.001). The result of this study shows that health behavior completely mediated the relationship between meaning in life and happiness related to aging among older adults (Z=4.17, <i>p</i><.001).Conclusion: It is necessary to promote health behavior to improve the happinessrelated to aging of older adults, especially during COVID-19.