The present study examined the role of vitality as a mediator of the association between dispositional hope and quality of life (QoL) (namely, physical health, psychological health, social relationships, and environment) in a sample of 101 adult primary care patients. Vitality was found to fully mediate the relationship between hope and physical health, social relationships, and environment. In addition, vitality was found to partially mediate the association between hope and psychological health. The present findings are consistent with a model in which vitality represents an important mechanism through which hope affects QoL in adults. Accordingly, these findings point to the importance of fostering both hope and vitality in efforts to promote positive QoL in adults.