This study examined the determinants of physical activity (PA) for older adults with Alzheimer’s disease (AD) to learn more about how to promote PA in this population. Caregivers of older adults with AD (N = 99) provided information related to care recipient’s PA, as well as addressed sociodemographics and perceptions about their care recipient’s PA. Gender of care recipient was a significant predictor of PA (β = .80, P < .05); men with AD participated in more PA than women with AD. Also, caregiver's outcome expectation for care recipient's PA also predicted more PA (β = .82, P < .05). Caregiver’s perceived benefits of PA (outcome expectation) for their care recipient partially mediated the relationship between self-efficacy for care recipient’s PA and the reported levels of PA for the care recipient. This study demonstrated the importance of caregiver perceptions about care recipient’s PA.