With the onset of the COVID-19 pandemic, many exercise programs moved online. The purpose of this study was to examine the extent to which older adults' social identification with other exercise program members contributed to their psychological flourishing and exercise program adherence. The study represented a secondary analysis of data derived from the Seniors COVID-19 Pandemic and Exercise (SCOPE) Trial, in which older adults were randomized to a waitlist control condition or one of two online (personal v group) exercise programs. Only data from participants in the trial intervention conditions (N = 162; M age = 73.52 years; SD = 5.61) were utilized in this secondary analysis. We assessed psychological flourishing and social identification at baseline and every two weeks, as well as program adherence over each 2-week block, for 12 weeks. Based on stepwise multilevel modeling the results revealed that older adults' social identification with others in their respective exercise program had a direct effect on psychological flourishing (ΔR 2 Unique Marginal = 0.063, p < .001) and program adherence (ΔR 2 Unique Marginal = 0.014, p = .03). The results highlight the value of bolstering older adults' social identification with others in an online exercise program to support adherence and well-being.