Older adults are at greater risk of complications from seasonal influenza, and promoting uptake and adherence to preventive behaviors is key to attenuating this risk. The current study examined the efficacy of a theory-based telephone-delivered intervention to promote uptake and maintenance of influenza preventive behaviors in a sample of Hong Kong residents 65 years and older. The intervention adopted a three-group randomized controlled design (n = 312) with two intervention conditions, motivational and motivational + volitional, and a measurement-only control condition. The primary outcome variable was self-reported compliance with influenza preventive behaviors, including washing hands, avoiding touching eyes, nose, or mouth, and wearing face masks. Secondary outcomes were theory-based psychological variables. Influenza preventive behaviors in participants in the motivational + volitional intervention group were significantly improved 3 months post-intervention relative to those in the control condition. However, participants in the intervention group demonstrated no difference in behavior at 6 and 12 months post-intervention relative to the participants in the control group. Intervention effects were observed on the theory-based social support, action planning, and coping planning variables. Although short-term benefits of the intervention were observed, effects appeared to be short-lived and future research should investigate more intensive interventions that lead to greater behavioral maintenance.