To examine the relative importance of social cognitive predictors (ie, performance accomplishment, vicarious learning, verbal persuasion, affective state) on health promotion self-efficacy among older adults during COVID-19. Cross-sectional. Data collected online from participants in British Columbia (BC), Canada. Seventy-five adults (n = 75) aged ≥65years. Health promotion self-efficacy was measured using the Self-Rated Abilities for Health Practices Scale. Performance accomplishment was assessed using the health directed behavior subscale of the Health Education Impact Questionnaire; vicarious learning was measured using the positive social interaction subscale of the Medical Outcomes Survey - Social Support Scale (MOS-SSS); verbal persuasion was assessed using the informational support subscale from the MOS-SSS; and affective state was assessed using the depression subscale from the Depression Anxiety Stress Scale (DASS-21). Multiple linear regression was used to investigate the relative importance of each social cognitive predictor on self-efficacy, after controlling for age. Our analyses revealed statistically significant associations between self-efficacy and performance accomplishment (health-directed behavior; β = .20), verbal persuasion (informational support; β = .41), and affective state (depressive symptoms; β = -.44) at P < .05. Vicarious learning (β = -.15) did not significantly predict self-efficacy. The model was statistically significant (P < .001) explaining 43% of the self-efficacy variance. Performance accomplishment experiences, verbal persuasion strategies, and affective states may be the target of interventions to modify health promotion self-efficacy among older adults, in environments that require physical and social distancing.