This article provides an overview of physical activity and its association with function, disability, and quality of life (QOL) outcomes among older adults. The rationale and the associated onset of chronic disease conditions that influence function, disability, and QOL is embedded in the "Graying of America". The literature reviewed in this article yielded 3 general conclusions: (1) there is an alarming rate of physical inactivity among older adults, particularly those aging with a disability; (2) there is strong evidence for the beneficial effects of physical activity on impairment, function, and health-related aspects of QOL among older adults, but there is less conclusive evidence for positive effects of physical activity on disability and global QOL; and (3) there is emerging support for self-efficacy as a mediator of the association between physical activity and disability, and QOL outcomes in older adults. Researchers should consider designing and testing programs that incorporate strategies for enhancing self-efficacy along with the promotion of physical activity as a means of preventing disablement and improving QOL among older adults. Such work will go a long way in identifying practical approaches that can be applied for improving the later years of life and is critical because many Americans will soon be affected by the aging of adults in the United States.